chore: migrate GitHub team references (#81)

Author: caugner

CONTRIBUTING.md

@@ -41,7 +41,7 @@ If you want to contribute but don't know where to start or can't find a suitable
 
 Once you find an issue you'd like to work on, please post a comment saying you want to work on it.
 Something like "I want to work on this" is fine.
-Also, mention the community team using the `@mdn/mdn-community-engagement` handle to ensure someone will get back to you.
+Also, mention the community team using the `@mdn/community` handle to ensure someone will get back to you.
 
 ## Asking for help