Bump mypy from 0.781 to 0.782

Bumps [mypy](https://github.com/python/mypy) from 0.781 to 0.782.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](https://github.com/python/mypy/compare/v0.781...v0.782)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements-dev.txt

@@ -7,7 +7,7 @@ coveralls==2.0.0
 flake8==3.8.3
 flake8-type-annotations==0.1.0
 flake8-tidy-imports==4.1.0
-mypy==0.781
+mypy==0.782
 pytest==5.4.3
 pytest-asyncio==0.14.0
 pytest-cov==2.10.0