Duplicates documentation in the README

The README contains these lines:

For string freeze breaks (which have rules for when they apply and when they don't), two approvals from the Translation Coordination team, open an issue (fill in the appropriate template).
For UI, feature, API, or hard code freeze breaks, two approvals from the release team. Reporting an issue here with a link to your merge request.
Contact us in both places for both approvals if your change breaks both string freeze and another freeze.

This information is also included in the wiki, on the freezes page.

Duplicating information like this is likely to cause issues - if the policy changes someone is likely to update the docs in one place and not another.