CPaster: Fix translation issue

Change-Id: Ic01818e3789d9d4bc2c8ebded167e1e81c798133
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/cpaster/authenticationdialog.h

@@ -35,6 +35,8 @@ namespace CodePaster {
 
 class AuthenticationDialog : public QDialog
 {
+    Q_OBJECT
+
 public:
     AuthenticationDialog(const QString &details, QWidget *parent = nullptr);