bpo-38010 Sync importlib.metadata with importlib_metadata 0.20. (GH-15646) (GH-15648)

Sync importlib.metadata with importlib_metadata 0.20.
(cherry picked from commit 102e9b40ff6ee45086a5f0d34d9c60c581a1e5e5)

Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>
4 files changed