CI(dependabot): Bump actions/upload-artifact from 3 to 4 (#105)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 3 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v3...v4)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  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>

.github/workflows/run-tox.yml

@@ -74,7 +74,7 @@ jobs:
         flags: pytest
         name: "luigi-tools-py${{ matrix.python-version }}-${{ matrix.min_versions }}"
     - name: Upload test artifacts
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       if: always()
       with:
         name: tests-${{ matrix.python-version }}-${{ matrix.min_versions }}