This update for python-typing_extensions fixes the following issues:

Update to version 3.7.4.2

* official support for Python 3.8 and 3.9

Update to version 3.7.4.1:

+ Fix isinstance() with generic protocol subclasses after subscripting
+ Fix tests for non-default interpreters
+ Use environment marker to specify typing dependency
+ Fix unions of protocols on Python 2


This update was imported from the openSUSE:Leap:15.2:Update update project.