[Mkdocs] Update Copyright + added Twitter Link

mkdocs.yml

@@ -1,6 +1,6 @@
 site_name: "mailcow: dockerized documentation"
 site_url: https://mailcow.github.io/mailcow-dockerized-docs/
-copyright: "Copyright © 2021 André Peters"
+copyright: "Copyright © 2022 André Peters & Community"
 repo_name: mailcow/mailcow-dockerized
 repo_url: https://github.com/mailcow/mailcow-dockerized
 edit_uri: ../mailcow-dockerized-docs/edit/master/docs/
@@ -152,6 +152,8 @@ extra:
       link: https://mailcow.email
     - icon: fontawesome/brands/github-alt
       link: https://github.com/mailcow
+    - icon: fontawesome/brands/twitter
+      link: https://twitter.com/mailcow_email    
 extra_css: [ extra.css ]
 extra_javascript: [ clients.js ]
 plugins: