Prevent publishing versions that aren't in the right format

[jelbourn]

We should block publishing any versions that do not conform to:
^\d+\.\d+\.\d+(-(beta|rc)\.\d+)?$

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}