Bump actions/upload-artifact from 3 to 4

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] <[email protected]>

.github/workflows/compile-fw.yml

@@ -56,7 +56,7 @@ jobs:
 
       - name: Save memory usage change report as artifact
         if: github.event_name == 'pull_request'
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: ${{ env.SKETCHES_REPORTS_PATH }}
           path: ${{ env.SKETCHES_REPORTS_PATH }}

.github/workflows/sync-labels.yml

@@ -70,7 +70,7 @@ jobs:
           file-url: https://raw.githubusercontent.com/107-systems/.github/main/workflow-templates/assets/sync-labels/${{ matrix.filename }}
 
       - name: Pass configuration files to next job via workflow artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           path: |
             *.yaml