Build(deps): Bump mypy-extensions from 0.4.1 to 0.4.2
Build(deps): Bump mypy-extensions from 0.4.1 to 0.4.2

Bumps [mypy-extensions](http://www.mypy-lang.org/) from 0.4.1 to 0.4.2.

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
aio-libs/aiosignal,aio-libs/aiosignal