Bump mypy from 0.991 to 1.2.0 (#358)

Bumps [mypy](https://github.com/python/mypy) from 0.991 to 1.2.0.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](python/mypy@v0.991...v1.2.0)

---
updated-dependencies:
- dependency-name: mypy
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Sam Bull <aa6bs0@sambull.org>

Author: dependabot[bot]

requirements.txt

@@ -1,7 +1,7 @@
 -e .
 build==0.10.0
 docutils==0.19
-mypy==0.991; implementation_name=="cpython"
+mypy==1.2.0; implementation_name=="cpython"
 pre-commit==2.21.0
 pytest==7.2.1
 pytest-asyncio==0.20.3