Change initial membership organisations to an explicitly curated list

This list needs to be written down before the PEP can be voted on /
approved.

Author: pradyunsg

peps/pep-0772.rst

@@ -292,10 +292,10 @@ includes:
   will be moved into the Packaging community.
 * Interested core team members: Any Python core team member who is willing to
   participate is welcome.
-* Wider community members: Non-profit organisations that participate in
-  packaging or working with new packagers. For example, PyOpenSci, NumFocus,
-  Django, are encouraged to initially nominate up to seven members by sending
-  an email to \[todo\].
+* Wider community members: An initial set of for-profit companies, nonprofit
+  organizations, academic or educational institutions and smaller unaffiliated
+  projects would be invited to nominate three individuals to represent them.
+  [TODO: add a link here for the initial set, that the authors curate]
 
 Adding a new member
 -------------------