Update Qt version in GitHub Actions workflow

Author: janakarana

.github/workflows/test.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Install Qt
         uses: jurplel/install-qt-action@v3
         with:
-          version: '6.2.4' 
+          version: '6.8.3' 
 
       - name: Change permission
         run: chmod +x src/MieSimulatorGUI.pro