Document new release process

[caugner]

What type of issue is this?

Other

What is the issue?

The release process has changed from manual PR'ing and GitHub release creation, to automatic release PR maintenance and automatic GitHub release creation, but this isn't documented yet.

What behavior were you expecting?

The new process should be documented, including what to do if things go wrong.

What version(s) of BCD is the issue present in?

• The current BCD release
• The current version of the main branch

Do you have anything more you want to share?

No response