fix(submodule): coerce deinit path to str for mypy

self.path is str | PathLike[str], but the deinit args list is typed List[str],
so mypy flagged the list item as incompatible (base.py:1297). Wrap it in str()
- this is the CI failure that put the PR back to draft. git submodule expects a
string path anyway, and the existing test (path="module") is unaffected.

Author: mvanhorn

git/objects/submodule/base.py

@@ -1294,7 +1294,7 @@ def deinit(self, force: bool = False) -> "Submodule":
         args: List[str] = []
         if force:
             args.append("--force")
-        args.extend(["--", self.path])
+        args.extend(["--", str(self.path)])
         self.repo.git.submodule("deinit", *args)
         return self