Add github bot support for multiple pre-req labels

[instructlab]

Add github bot support for multiple pre-req labels

[russellb]

@cdoern I just changed the title and description of this to reflect what I think needs to be done. I think most of the code will "just work" since the icli workflow is the same. The one piece we're missing is the access control side in the gobot configuration file. We allow requiring a label to be set on PRs, but now we need to be able to check for multiple labels.

[russellb]

some info starting from here: instructlab/instructlab#702

[russellb]

Updated this to blocking priority -- before taxonomy is opened up, we need to configure the bot to require triage OR knowledge labels to be set. See access control docs here - https://github.com/instruct-lab/enhancements/blob/main/docs/github-taxonomy-automation.md

The quickest change is to turn the field in the config from a single item to a list, and in the code, treat the list as a set of OR conditions

[russellb]

If you want to get super fancy, you could allow comma separated labels within each list item where you treat all of those as AND.

That way we can configure any combination of OR + AND logic needed

[russellb]

Implemented in #193