Soften language on Packaging workgroup members becoming voters

They might not want to become a voting member, or be appropriately
available to do so.

Author: pradyunsg

peps/pep-0772.rst

@@ -289,7 +289,7 @@ includes:
 * PyPA members: Anyone with the triage bit or commit bit, or at least one
   project in the PyPA organisation.
 * Packaging workgroup members: Anyone who is listed on the Packaging WG charter
-  will be moved into the Packaging community.
+  who is willing to participate is welcome.
 * Interested core team members: Any Python core team member who is willing to
   participate is welcome.
 * Wider community members: An initial set of for-profit companies, nonprofit