Fix compat bug with napari 0.4.18

Author: jeylau

setup.cfg

@@ -33,7 +33,7 @@ project_urls =
 packages = find:
 install_requires =
     dask-image
-    napari==0.4.17
+    napari==0.4.18
     natsort
     numpy
     opencv-python-headless

src/napari_deeplabcut/_widgets.py

@@ -283,7 +283,7 @@ def __init__(self, napari_viewer):
         status_bar.addPermanentWidget(self.last_saved_label)
 
         # Hack napari's Welcome overlay to show more relevant instructions
-        overlay = self.viewer.window._qt_viewer._canvas_overlay
+        overlay = self.viewer.window._qt_viewer._welcome_widget
         welcome_widget = overlay.layout().itemAt(1).widget()
         welcome_widget.deleteLater()
         w = QtWelcomeWidget(None)