feat: Upgrade to python 3.10

[lucyb]

The applications that use this library run python 3.10 and python 3.12. The outdated version of python is also stopping us from merging dependency updates.

This change should also make it easier for us to do #269.

[StevenMaude]

thought: It's not essential, but we could rebuild the requirements; it drops one dependency (importlib-metadata which was used for Python 3.9 support alone).

Edit: actually two, because there was another transitive one.

diff --git a/requirements.dev.txt b/requirements.dev.txt
index 2269502..f31214d 100644
--- a/requirements.dev.txt
+++ b/requirements.dev.txt
@@ -1,5 +1,5 @@
 #
-# This file is autogenerated by pip-compile with Python 3.9
+# This file is autogenerated by pip-compile with Python 3.10
 # by the following command:
 #
 #    pip-compile --allow-unsafe --generate-hashes --output-file=requirements.dev.txt requirements.dev.in
@@ -173,10 +173,6 @@ identify==2.6.15 \
     --hash=sha256:1181ef7608e00704db228516541eb83a88a9f94433a8c80bb9b5bd54b1d81757 \
     --hash=sha256:e4f4864b96c6557ef2a1e1c951771838f4edc9df3a72ec7118b338801b11c7bf
     # via pre-commit
-importlib-metadata==8.7.1 \
-    --hash=sha256:49fef1ae6440c182052f407c8d34a68f72efc36db9ca90dc0113398f2fdde8bb \
-    --hash=sha256:5a1f80bf1daa489495071efbb095d75a634cf28a8bc299581244063b53176151
-    # via build
 iniconfig==2.1.0 \
     --hash=sha256:3abbd2e30b36733fee78f9c7f7308f2d0050e88f0087fd25c2645f63c773e1c7 \
     --hash=sha256:9deba5723312380e77435581c6bf4935c94cbfab9b1ed33ef8d238ea168eb760
@@ -205,9 +201,9 @@ pip-tools==7.5.3 \
     --hash=sha256:3aac0c473240ae90db7213c033401f345b05197293ccbdd2704e52e7a783785e \
     --hash=sha256:8fa364779ebc010cbfe17cb9de404457ac733e100840423f28f6955de7742d41
     # via -r requirements.dev.in
-platformdirs==4.4.0 \
-    --hash=sha256:abd01743f24e5287cd7a5db3752faf1a2d65353f38ec26d98e25a6db65958c85 \
-    --hash=sha256:ca753cf4d81dc309bc67b0ea38fd15dc97bc30ce419a7f58d13eb3bf14c4febf
+platformdirs==4.10.0 \
+    --hash=sha256:31e761a6a0ca04faf7353ea759bdba55652be214725111e5aac52dfa29d4bef7 \
+    --hash=sha256:fb516cdb12eb0d857d0cd85a7c57cea4d060bee4578d6cf5a14dfdf8cbf8784a
     # via
     #   -c requirements.prod.txt
     #   black
@@ -459,10 +455,6 @@ wheel==0.47.0 \
     --hash=sha256:212281cab4dff978f6cedd499cd893e1f620791ca6ff7107cf270781e587eced \
     --hash=sha256:cc72bd1009ba0cf63922e28f94d9d83b920aa2bb28f798a31d0691b02fa3c9b3
     # via pip-tools
-zipp==3.23.1 \
-    --hash=sha256:0b3596c50a5c700c9cb40ba8d86d9f2cc4807e9bedb06bcdf7fac85633e444dc \
-    --hash=sha256:32120e378d32cd9714ad503c1d024619063ec28aad2248dc6672ad13edfa5110
-    # via importlib-metadata
 
 # The following packages are considered to be unsafe in a requirements file:
 pip==26.0.1 \
diff --git a/requirements.prod.txt b/requirements.prod.txt
index 4eb8b8e..d1b7f17 100644
--- a/requirements.prod.txt
+++ b/requirements.prod.txt
@@ -1,5 +1,5 @@
 #
-# This file is autogenerated by pip-compile with Python 3.9
+# This file is autogenerated by pip-compile with Python 3.10
 # by the following command:
 #
 #    pip-compile --allow-unsafe --generate-hashes --output-file=requirements.prod.txt requirements.prod.in
@@ -10,13 +10,13 @@ attrs==26.1.0 \
     # via
     #   cattrs
     #   requests-cache
-cattrs==25.3.0 \
-    --hash=sha256:1ac88d9e5eda10436c4517e390a4142d88638fe682c436c93db7ce4a277b884a \
-    --hash=sha256:9896e84e0a5bf723bc7b4b68f4481785367ce07a8a02e7e9ee6eb2819bc306ff
+cattrs==26.1.0 \
+    --hash=sha256:d1e0804c42639494d469d08d4f26d6b9de9b8ab26b446db7b5f8c2e97f7c3096 \
+    --hash=sha256:fa239e0f0ec0715ba34852ce813986dfed1e12117e209b816ab87401271cdd40
     # via requests-cache
-certifi==2026.5.20 \
-    --hash=sha256:3c52e209ba0a4ad7aebe60436a4ab349c39e1e602e8c134221e546902ad25897 \
-    --hash=sha256:69dea482ab64caa7b9f6aba1c6bf48bb6a5448d1c0f1b17ab42ad8c763a5344d
+certifi==2026.6.17 \
+    --hash=sha256:024c88eeec92ca068db80f02b8b07c9cef7b9fe261d1d535abfd5abd6f6af432 \
+    --hash=sha256:2227dcbaafe0d2f59279d1762ddddc37783ed4354594f194ffc31d20f41fc3db
     # via requests
 charset-normalizer==3.4.7 \
     --hash=sha256:007d05ec7321d12a40227aae9e2bc6dca73f3cb21058999a1df9e193555a9dcc \
@@ -157,9 +157,9 @@ furl==2.1.4 \
     --hash=sha256:877657501266c929269739fb5f5980534a41abd6bbabcb367c136d1d3b2a6015 \
     --hash=sha256:da34d0b34e53ffe2d2e6851a7085a05d96922b5b578620a37377ff1dbeeb11c8
     # via -r requirements.prod.in
-idna==3.15 \
-    --hash=sha256:048adeaf8c2d788c40fee287673ccaa74c24ffd8dcf09ffa555a2fbb59f10ac8 \
-    --hash=sha256:ca962446ea538f7092a95e057da437618e886f4d349216d2b1e294abfdb65fdc
+idna==3.18 \
+    --hash=sha256:7f952cbe720b688055e3f87de14f5c3e5fdaa8bc3928985c4077ca689de849a2 \
+    --hash=sha256:ffb385a7e039654cef1ab9ef32c6fafe283c0c0467bba1d9029738ce4a14a848
     # via
     #   requests
     #   url-normalize
@@ -167,13 +167,13 @@ orderedmultidict==1.0.2 \
     --hash=sha256:16a7ae8432e02cc987d2d6d5af2df5938258f87c870675c73ee77a0920e6f4a6 \
     --hash=sha256:ab5044c1dca4226ae4c28524cfc5cc4c939f0b49e978efa46a6ad6468049f79b
     # via furl
-platformdirs==4.4.0 \
-    --hash=sha256:abd01743f24e5287cd7a5db3752faf1a2d65353f38ec26d98e25a6db65958c85 \
-    --hash=sha256:ca753cf4d81dc309bc67b0ea38fd15dc97bc30ce419a7f58d13eb3bf14c4febf
+platformdirs==4.10.0 \
+    --hash=sha256:31e761a6a0ca04faf7353ea759bdba55652be214725111e5aac52dfa29d4bef7 \
+    --hash=sha256:fb516cdb12eb0d857d0cd85a7c57cea4d060bee4578d6cf5a14dfdf8cbf8784a
     # via requests-cache
-requests==2.32.5 \
-    --hash=sha256:2462f94637a34fd532264295e186976db0f5d453d1cdd31473c85a6a161affb6 \
-    --hash=sha256:dbba0bac56e100853db0ea71b82b4dfd5fe2bf6d3754a8893c3af500cec7d7cf
+requests==2.34.2 \
+    --hash=sha256:2a0d60c172f83ac6ab31e4554906c0f3b3588d37b5cb939b1c061f4907e278e0 \
+    --hash=sha256:f288924cae4e29463698d6d60bc6a4da69c89185ad1e0bcc4104f584e960b9ed
     # via
     #   -r requirements.prod.in
     #   requests-cache
@@ -193,13 +193,13 @@ typing-extensions==4.15.0 \
     # via
     #   cattrs
     #   exceptiongroup
-url-normalize==2.2.1 \
-    --hash=sha256:3deb687587dc91f7b25c9ae5162ffc0f057ae85d22b1e15cf5698311247f567b \
-    --hash=sha256:74a540a3b6eba1d95bdc610c24f2c0141639f3ba903501e61a52a8730247ff37
+url-normalize==3.0.0 \
+    --hash=sha256:0552cbf2831a32a28994a13d29bca58a60e10ff6c0380e343ec6d1c2a0d232d8 \
+    --hash=sha256:95234bd359f86831c1fd87c248877f2a6887db2f3b5087120083f2fffcba4889
     # via requests-cache
-urllib3==2.6.3 \
-    --hash=sha256:1b62b6884944a57dbe321509ab94fd4d3b307075e0c2eae991ac71ee15ad38ed \
-    --hash=sha256:bf272323e553dfb2e87d9bfd225ca7b0f467b919d7bbd355436d3fd37cb0acd4
+urllib3==2.7.0 \
+    --hash=sha256:231e0ec3b63ceb14667c67be60f2f2c40a518cb38b03af60abc813da26505f4c \
+    --hash=sha256:9fb4c81ebbb1ce9531cce37674bbc6f1360472bc18ca9a553ede278ef7276897
     # via
     #   requests
     #   requests-cache

[lucyb]

thought: It's not essential, but we could rebuild the requirements; it drops one dependency (importlib-metadata which was used for Python 3.9 support alone).

That's a really good point, thank you. Unfortunately, upgrading has broken something. I'll try to come back to it tomorrow, but if it's obvious to you or you have time, please do step in.

[StevenMaude]

@lucyb: it wasn't immediately obvious, but a case where Black and Ruff formatting conflicted 🙃

I removed Black, and did that in a separate branch with a PR into this branch, just because that felt tidier than unexpectedly adding to your branch.

Feel free to just cherry-pick/squash my commit here, and close my PR 😃