docs(RELEASE_MANAGEMENT): explain auto-merge for release PRs is a no-no

[petermetz]

The detailed explanation is here:

Do not enable auto-merging on GitHub for the pull request doing the release.
The problem with auto-merging here is that it would modify the release commit's SHA as the
rebase would happen on GitHub's servers where your git signing identity is not available to use
given that GitHub does (should) not have access to your private key for signing.
The way the preserve your commit signature as valid the commit SHA must remain the same and the
way to achieve this is to perform the pull request merging with fast forward. The merging
ensures that there is no commit SHA change and the --ff-only option ensures that there is no
merge commit to throw a wrench in the process.

Signed-off-by: Peter Somogyvari peter.somogyvari@accenture.com

Pull Request Requirements

• Rebased onto upstream/main branch and squashed into single commit to help maintainers review it more efficient and to avoid spaghetti git commit graphs that obfuscate which commit did exactly what change, when and, why.
• Have git sign off at the end of commit message to avoid being marked red. You can add -s flag when using git commit command. You may refer to this link for more information.
• Follow the Commit Linting specification. You may refer to this link for more information.

Character Limit

• Pull Request Title and Commit Subject must not exceed 72 characters (including spaces and special characters).
• Commit Message per line must not exceed 80 characters (including spaces and special characters).

A Must Read for Beginners
For rebasing and squashing, here's a must read guide for beginners.