doc: revise Collaborator description in GOVERNANCE.md

* Active voice
* Remove Node.js Foundation mention. It may be appropriate to add
  something back in when the new foundation is bootstrapped. We
  don't control membership criteria, so best to link to something else
  when it becomes available rather than make guarantees in this doc.

PR-URL: https://github.com/nodejs/node/pull/27071


Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>