fix(deps): update dependency scratch-paint to v4.0.21

Author: renovate[bot]

packages/scratch-gui/package.json

@@ -118,7 +118,7 @@
     "scratch-audio": "2.0.241",
     "scratch-blocks": "1.1.225",
     "scratch-l10n": "6.0.67",
-    "scratch-paint": "4.0.3",
+    "scratch-paint": "4.0.21",
     "scratch-render-fonts": "1.0.242",
     "scratch-storage": "4.1.17",
     "startaudiocontext": "1.2.1",