Add attributes to package manager modules (#5954)

Add attributes to package manager modules.

plugins/modules/yarn.py

@@ -20,6 +20,13 @@ description:
 author:
   - "David Gunter (@verkaufer)"
   - "Chris Hoffman (@chrishoffman), creator of NPM Ansible module)"
+extends_documentation_fragment:
+  - community.general.attributes
+attributes:
+  check_mode:
+    support: full
+  diff_mode:
+    support: none
 options:
   name:
     type: str