Bump tsuyoshicho/action-mypy from 3 to 4

Bumps [tsuyoshicho/action-mypy](https://github.com/tsuyoshicho/action-mypy) from 3 to 4.
- [Release notes](https://github.com/tsuyoshicho/action-mypy/releases)
- [Commits](tsuyoshicho/action-mypy@v3...v4)

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

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

.github/workflows/linter.yml

@@ -51,7 +51,7 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
     - name: mypy
-      uses: tsuyoshicho/action-mypy@v3
+      uses: tsuyoshicho/action-mypy@v4
       with:
         github_token: ${{ secrets.github_token }}
         reporter: github-pr-review