Is your enhancement related to a problem? Please describe.

During the release process (described in RELEASING.md) we're currently:

1. creating a pull request with the release changes (version bump, readme updates, etc.),
2. merging in the pull request to `master,
3. creating a new release in GitHub which creates a new tag for that latest revision of master.

With the introduction of master deploys to WP-org trunk in #734, it now:

1. pushed the upcoming release to WP-org SVN trunk (even though it hasn't been tagged and deployed yet).
2. pushes the SVN tag/x.x.x when the release is tagged and the CI runs.

This leads to the following warning on WP.org during step 1 and 2:

Proposed Solution

Introduce a trunk branch which is updated only after releases (possibly by the release workflow)?

Use it for isolated updates to readme and WP-org assets. Automatically merge it back to master if there are differences.

Designs

No response

Describe alternatives you've considered

No response

Please confirm that you have searched existing issues in this repository.

Yes