Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v3...v4)

---
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/main.yml

@@ -73,7 +73,7 @@ jobs:
 
       - name: Restore mypy cache
         if: matrix.task.name == 'Type check'
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: .mypy_cache
           key: mypy-${{ env.CACHE_PREFIX }}-${{ runner.os }}-${{ matrix.python }}-${{ hashFiles('*requirements.txt') }}-${{ github.ref }}-${{ github.sha }}