updated gtk backend

mablue · web-flow · commit c03532c430af · 2022-09-27T09:08:21.000+03:30
for fixing this error:
```
  File "/home/mab/.local/lib/python3.10/site-packages/matplotlib/backends/_backend_gtk.py", line 236, in resize
    toolbar_size = self.toolbar.size_request()
AttributeError: 'NavigationToolbar2GTK4' object has no attribute 'size_request'. Did you mean: 'get_size_request'?
```
diff --git a/lib/matplotlib/backends/_backend_gtk.py b/lib/matplotlib/backends/_backend_gtk.py
@@ -233,7 +233,7 @@ def resize(self, width, height):
         width = int(width / self.canvas.device_pixel_ratio)
         height = int(height / self.canvas.device_pixel_ratio)
         if self.toolbar:
-            toolbar_size = self.toolbar.size_request()
+            toolbar_size = self.toolbar.get_size_request()
             height += toolbar_size.height
         canvas_size = self.canvas.get_allocation()
         if self._gtk_ver >= 4 or canvas_size.width == canvas_size.height == 1:
