Fix for sizeHint: it must return QSizeF

Close https://github.com/wkentaro/labelme/issues/1201

labelme/widgets/label_list_widget.py

@@ -61,9 +61,9 @@ class HTMLDelegate(QtWidgets.QStyledItemDelegate):
 
     def sizeHint(self, option, index):
         thefuckyourshitup_constant = 4
-        return QtCore.QSizeF(
-            self.doc.idealWidth(),
-            self.doc.size().height() - thefuckyourshitup_constant,
+        return QtCore.QSize(
+            int(self.doc.idealWidth()),
+            int(self.doc.size().height() - thefuckyourshitup_constant),
         )