Upgrade to upload-artifact v4

Author: PerThomasHaga

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
         github-token: ${{ secrets.GITHUB_TOKEN }}
 
     - name: Upload JUnit Test Results
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       if: always()
       with:
         name: junit-results