Use QEnterEvent for QWidget::enterEvent on Qt 6 (#4365)

* fix: use concrete QEnterEvent on Qt 6

* chore: add changelog entry

src/widgets/helper/Button.cpp

@@ -217,7 +217,11 @@ void Button::fancyPaint(QPainter &painter)
     }
 }
 
-void Button::enterEvent(QEvent *)
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+void Button::enterEvent(QEnterEvent * /*event*/)
+#else
+void Button::enterEvent(QEvent * /*event*/)
+#endif
 {
     this->mouseOver_ = true;
 }