Upgrade to release 3.7.4.3:
- Add SupportsIndex, added in Python 3.8
- Make tests for Annotated work with Python 3.9
- Add PEP 613 TypeAlias to typing_extensions
- Add tox.ini for typing_extensions
- Remove extra 'use' in readme
Signed-off-by: Leon Anavi <leon.anavi@konsulko.com>
Acked-by: Trevor Gamblin <trevor.gamblin@windriver.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
