Bump actions/upload-artifact from 2 to 4

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 2 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/v2...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>

.github/workflows/CI.yml

@@ -26,7 +26,7 @@ jobs:
           echo "isotag=${VER}-${REL}" >> $GITHUB_ENV
 
       - name: Upload iso artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: mbp-ubuntu-${{ steps.tag.outputs.tag }}.z01
           path: ${{ github.workspace }}/output/*