docs: link upstream sync section in MAINTAINING to CONTRIBUTING (#5075)

* Link upstream sync section in MAINTAINING to CONTRIBUTING

* Update MAINTAINING.md table of contents

Co-authored-by: Joe Previte <jjprevite@gmail.com>

Asher committed 4y ago

3ba3caa8a67a71f07054d515075f79d5efc621f7

Parent: f0bfd3b

Committed by GitHub <noreply@github.com> on 4/7/2022, 8:15:30 PM