[DOC] Add documentation for security configuration upgrade feature

[peternied]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request and all versions that are affected.
The security plugin is adding an API to upgrading the security configuration as new default changes are included.

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

• [FEATURE] New reserved roles are not sourced to security index on an upgrade security#2316
• [Feature] Check for and perform upgrades on security configurations security#4102

[hdhalter]

Thanks, @peternied !s this going out in 2.13?

[peternied]

Yes, this will go out with 2.13