Bump version to 0.13.0
This contains:
- https://gitlab.com/gitlab-org/gitlab-triage/merge_requests/70
- https://gitlab.com/gitlab-org/gitlab-triage/merge_requests/72
- https://gitlab.com/gitlab-org/gitlab-triage/merge_requests/73
- https://gitlab.com/gitlab-org/gitlab-triage/merge_requests/74
- https://gitlab.com/gitlab-org/gitlab-triage/merge_requests/75