Let mypy ignore distutils

I don't know if there are any type hints still available anywhere; it's
probably a mistake to continue using distutils just for text parsing
that setuptools normally does.

setup.cfg

@@ -25,6 +25,10 @@ ignore = E241,E501,E261,E126,E127,E128,E302,W503
 [mypy-setuptools.command.egg_info]
 ignore_missing_imports = true
 
+# distutils got removed from Python 3.12, setuptools ships it now but w/o hints
+[mypy-distutils.text_file]
+ignore_missing_imports = true
+
 # zest.releaser has no type hints
 [mypy-zest.releaser.utils]
 ignore_missing_imports = true