🧎‍♀️ Genuflect to the types.

Under some circumstances not fully understood, mypy has started complaining when `_validate_project` tries to import `trove_classifiers` (and it doesn't exist), even though `_validate_project` is excluded from mypy checks. Mysteriously, adding `trove_classifiers` itself to the list of modules for which to ignore imports suppresses this mysterious failure.

Ref pypa#4296.

Author: jaraco

mypy.ini

@@ -25,7 +25,8 @@ disable_error_code = attr-defined
 #   https://github.com/pypa/setuptools/pull/3979#discussion_r1367968993
 # - distutils._modified has different errors on Python 3.8 [import-untyped], on Python 3.9+ [import-not-found]
 # - All jaraco modules are still untyped
-[mypy-pkg_resources.extern.*,setuptools.extern.*,distutils._modified,jaraco.*]
+# - _validate_project sometimes complains about trove_classifiers (#4296)
+[mypy-pkg_resources.extern.*,setuptools.extern.*,distutils._modified,jaraco.*,trove_classifiers]
 ignore_missing_imports = True
 
 # - pkg_resources tests create modules that won't exists statically before the test is run.