feat: trigger validators on issue_comment

[andekande]

when a PR comment is created or edited the relevant validators will now recheck the conditions
this is to enable support for, eg:

  - when: issue_comment.created, issue_comment.edited
    name: 'Merge Quality Check'
    validate:
      # validate missing Jira ticket as failure
      - do: title
        must_include:
          regex: '^\[?([A-Za-z]+-\d+)\]?:? '
          message: 'A Jira Ticket ID is not present in the PR title.'
      # validate presence of work-in-progress label as failure
      - do: label
        must_exclude:
          regex: 'work in progress|wip|do not merge'
          message: 'A label indicates work in progress. Do not release yet.'
    pass:
      - do: checks
        status: 'success'
        payload:
          title: 'Qualified For Merge'
    fail:
      - do: checks
        status: 'failure'
        payload:
          title: 'Not Qualified For Merge'