Bump actions/cache from 3.3.2 to 4.0.0

Bumps [actions/cache](https://github.com/actions/cache) from 3.3.2 to 4.0.0.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v3.3.2...v4.0.0)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/tests.yaml

@@ -45,7 +45,7 @@ jobs:
           pip install -U setuptools
           python -m pip install -U pip
       - name: cache mypy
-        uses: actions/cache@v3.3.2
+        uses: actions/cache@v4.0.0
         with:
           path: ./.mypy_cache
           key: mypy|${{ matrix.python }}|${{ hashFiles('pyproject.toml') }}