Update Qt version to latest 5.16 stable release

Author: SaschaWillems

.github/workflows/build.yml

@@ -94,7 +94,7 @@ jobs:
 
       - uses: jurplel/install-qt-action@v3
         with:
-          version: 5.12.9
+          version: 5.15.2
           host: mac
 
       - name: Prepare Vulkan SDK