Update approvaltests requirement from >=18.2.0 to >=19.0.0 - #196

Sourced from approvaltests's releases.

Clean up Namer API

Changed Namer:

- def get_received_filename(self, base) -> str:
+ def get_received_filename(self) -> str:

this should only effect people that have made their own namers.

Minor

We also reset the minimum required version of pytest back to 4.0.0

• 345a0ca . d tidy code and update markdown snippets
• c8c83f2 - B accept pytest 4.0.0
• 46705ee . d tidy code and update markdown snippets
• 7edd73e Merge pull request #264 from approvals/JayBazuzi/remove-Namer-base
• f495e02 *** remove parameter base from Namer
• eb0b06d . e use sudo instead of running elevated
• 048393d . e beyond compare
• 5fb8a44 . e build_and_test
• e1dc8aa . e chrome
• e99b469 . e refresh
• Additional commits viewable in compare view