Deprecate irker in favour of the "t2bot GitLab bot"
https://gitlab.com/gitlab-org/gitlab/issues/14190
I have deactivated irker in all currently active (non-archived) projects in the @chakra group.
I have also removed all "t2bot GitLab bot" configuration from said projects, and set a single configuration on the group level of @chakra, which applies to all projects.