ci: skip CI for draft and WIP PRs

Let only the init stage run so that we have a link on PRs to the CI and
can trigger it manually if desired. PR template updated with this info.
Also use yaml anchors for rules to reduce duplication.

.github/PULL_REQUEST_TEMPLATE.md

@@ -23,4 +23,14 @@ test/README.md and add these additional items:
 - [ ] QE has approved reproducer/new tests and
 - [ ] Subsequent commits provide bug fixes without modifying the reproducer; CI reports PASS and
 - [ ] QE approves this PR; RHBZ status is set to `MODIFIED + Verified=Tested`
+
+Information regarding our GitLab pipeline (Schutzbot):
+
+CI will not be ran automatically if WIP label is applied or the PR is in DRAFT state, instead only
+a link will be provided to the pipeline which can then be triggered manually if desired. To run the
+CI automatically either switch the PR to ready or apply WIP+test label.
+
+Outside contributors need manual approval from one of the osbuild-composer maintainers.
+
+Schutzbot will only be triggered if all Tests jobs in GitHub workflow succeed.
 -->

.github/workflows/trigger-gitlab.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     env:
       SCHUTZBOT_SSH_KEY: ${{ secrets.SCHUTZBOT_SSH_KEY }}
-      SKIP_CI: ${{ github.event.pull_request.draft == true || contains(github.event.pull_request.labels.*.name, 'WIP') }}
+      SKIP_CI: ${{ (github.event.pull_request.draft == true || contains(github.event.pull_request.labels.*.name, 'WIP')) && !contains(github.event.pull_request.labels.*.name, 'WIP+test') }}
     steps:
       - name: Report status
         uses: haya14busa/action-workflow_run-status@v1
@@ -59,5 +59,5 @@ jobs:
           touch ~/.ssh/known_hosts
           ssh-keyscan -t rsa gitlab.com >> ~/.ssh/known_hosts
           git remote add ci git@gitlab.com:osbuild/ci/osbuild-composer.git
-          [[ "${SKIP_CI}" == true ]] && PUSH_OPTION="-o ci.skip" || PUSH_OPTION=""
+          [[ "${SKIP_CI}" == true ]] && PUSH_OPTION='-o ci.variable="SKIP_CI=true"' || PUSH_OPTION=""
           git push -f ${PUSH_OPTION} ci