mypy

425fb0b4 - [1.0 backport] Adjust SCC setup to enable earlier collections.abc import in typeshed (#14531)

[1.0 backport] Adjust SCC setup to enable earlier collections.abc import in typeshed (#14531) A backport of #14088 to the `release-1.0` branch. Co-authored-by: Michael Lee <michael.lee.0x2a@gmail.com>