Move from mypy master to PyPI.

As mypy 1.11 is released we no longer need to install
directly from the git master but can install from
PyPI as usual.

setup.cfg

@@ -67,7 +67,7 @@ tests =
     # pooch is an optional scipy dependency for getting datasets
     pooch
 typing =
-    mypy @ git+https://github.com/python/mypy
+    mypy>=1.11
     # needed otherwise pytest decorators don't get typed properly
     pytest
 examples =