tox: update mypy to v2.1.0

Update the fixed mypy version to its most recent.

Signed-off-by: James Knight <git@jdknight.me>

Author: jdknight

tox.ini

@@ -91,7 +91,7 @@ commands =
 deps =
     {[testenv]deps}
     -r{toxinidir}/requirements_types.txt
-    mypy: mypy==1.20.0
+    mypy: mypy==2.1.0
 commands =
     mypy \
     --explicit-package-bases \