Bump mypy from 0.781 to 0.782 in /docs (#439)

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

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

docs/requirements.txt

@@ -11,5 +11,5 @@ tomlkit==0.6.0
 
 # Dependencies of our project:
 typing-extensions==3.7.4.2
-mypy==0.781
+mypy==0.782
 pytest==5.4.3