build(deps): 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/ci.yml

@@ -70,7 +70,7 @@ jobs:
 
       - name: Mypy
         if: ${{ always() }}
-        uses: tsuyoshicho/action-mypy@v3
+        uses: tsuyoshicho/action-mypy@v4
         with:
           reporter: github-pr-review
           fail_on_error: true