Start tagging RC releases in gitHub

User story:
As a Developer of the company where we use PMM as a base for our own customization I want to be able to create test builds for my team. I want builds to be created from RC releases Percona start publishing for the community.
To do this I need to be able to get the code for RC by using tags from GitHub

https://percona.community/blog/2021/10/15/preview-release/

UI/UX: N/A

Acceptance criteria

• all PMM repos have tags pointing to RC code (in addition to releases tags we adding )

Out of scope:

• TBD

Suggested implementation:
TBD

How to test:
TBD