GODT-1336: Fix showing window on startup

internal/frontend/qt/frontend.go

@@ -15,6 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
 
+//go:build build_qt
 // +build build_qt
 
 // Package qt provides communication between Qt/QML frontend and Go backend
@@ -64,7 +65,7 @@ type FrontendQt struct {
 	initializationDone sync.Once
 
 	app    *widgets.QApplication
-	engine *qml.QQmlApplicationEngine
+	engine *qml.QQmlEngine
 	qml    *QMLBackend
 }