Document how to use github bot under matrix channel

[heads-gh-bot]

Users not wanting to create a github username, or complainsing about github not being tor friendly, or whatever other reason won't have any reason to not open issues anymore.

[tlaurion]

To create issue under Heads repo

!heads create <title> [description] [labels] - Create an issue for this repo
!heads assign [number] [...users] - Assign an issue to a user. If number is ommitted, the latest issue is used. If users is omitted, you are assigned.
!heads close <number> [comment] - Close an issue
!heads workflow run <name> [args] [ref] - Run a GitHub Actions workflow. Args should be specified in "key=value,key2='value 2'" format.
!heads help - This help text

To create issue under Heads-wiki repo:

!heads-wiki create <title> [description] [labels] - Create an issue for this repo
!heads-wiki assign [number] [...users] - Assign an issue to a user. If number is ommitted, the latest issue is used. If users is omitted, you are assigned.
!heads-wiki close <number> [comment] - Close an issue
!heads-wiki workflow run <name> [args] [ref] - Run a GitHub Actions workflow. Args should be specified in "key=value,key2='value 2'" format.
!heads-wiki help - This help text

Note:

• For @heads-gh-bot to behave without powers: it has only read permissions over repo. This still means that @heads-gh-bot can close issues he created, but those will appear in channel anyway, including the commands. Good enough