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](actions/upload-artifact@v2...v4)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/ci_run_scm_rts.yml

@@ -217,7 +217,7 @@ jobs:
         ./cmp_rt2bl.py --dir_rt ${dir_rt} --dir_bl ${dir_bl}
 
     - name: Upload plots of SCM Baselines/RTs as GitHub Artifact.
-      uses: actions/upload-artifact@v2
+      uses: actions/upload-artifact@v4
       with:
         name: rt-plots-${{matrix.build-type}}
         path: /home/runner/work/ccpp-scm/ccpp-scm/test/scm_rt_out