fix: testing project generation.

Author: paulhazen

.github/workflows/generate-unity-project-files.yml

@@ -32,7 +32,7 @@ jobs:
           unity-editor -batchmode -quit -nographics -logFile -executeMethod UnityEditor.SyncVS.SyncSolution
 
       - name: Upload Solution Files
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: UnitySolution
           path: "*.sln"