fix(deps): update dependency permission_handler to v12

Author: renovate[bot]

pubspec.yaml

@@ -64,7 +64,7 @@ dependencies:
   palette_generator: ^0.3.3+3
   path: ^1.9.0
   path_provider: ^2.1.2
-  permission_handler: ^11.3.1
+  permission_handler: ^12.0.0
   phoenix_theme:
     git:
       url: https://github.com/ubuntu-flutter-community/phoenix_theme