docs: Update community slack inviter link

Signed-off-by: Charlie Egan <[email protected]>

Author: charlieegan3

Diff for: docs/website/content/community/_index.md

@@ -18,7 +18,7 @@ sections:
       note: |
         Primary channel for community support and OPA maintainer discussions.
         Join #help for support.
-      link: https://inviter.co/opa/
+      link: https://inviter.co/opa
       link_text: Join us on Slack
     - title: GitHub
       icon: /img/community-logos/github.png
@@ -173,4 +173,4 @@ sections:
       icon: /img/community-logos/meetup.png
       link: mailto:[email protected]?subject=Host%20an%20OPA%20Meetup
       link_text: Host a Meetup
----
+---