Add branch protection rule

[CodexRaunak]

I was updating the readme.md and the auto-merge workflow auto-merged my PR without any approval for any reviewer. This can lead anyone to merge anything to the repo.

Fix:

• To set up branch protection rule (like only merge after the validation-metadata check passes).
• For my old repo I had added the validation-metadata check as a ruleset.

[jonesbusy]

Should be fixed

Not sure if the require up to date branches is very useful since we create timestamped files