Update existing documentation

[SirAionTech]

Is your feature request related to a problem?
No.

Describe the solution you'd like
The documentation that explains "how to become PSC" throughout OCA should point to this repo's documentation https://oca.github.io/repo-maintainer-conf.

Describe alternatives you've considered
Updating the documentation of https://odoo-community.org.

Additional context
For instance, https://odoo-community.org/get-involved/contribute still says

Application is sent by the sponsor to the email address below with links allowing its contributions to be evaluated

[github-actions]

There hasn't been any activity on this issue in the past 6 months, so it has been marked as stale and it will be closed automatically if no further activity occurs in the next 30 days.
If you want this issue to never become stale, please ask a PSC member to apply the "no stale" label.