[tests] trigger cubicweb builds from yams if all other tests passed

.gitlab-ci.yml

 image: python
 
+stages:
+  - tests
+  - after-tests
+
 before_script:
   - pip install tox
 
 flake8:
+  stage: tests
   script: tox -e flake8
 
 py3:
+  stage: tests
   script: tox -e py3
 
 py3-from-forge:
+  stage: tests
   script: tox -e py3-from-forge
 
 check-manifest:
+  stage: tests
   script: tox -e check-manifest
 
 black:
+  stage: tests
   script: tox -e black
 
 mypy:
+  stage: tests
   script: tox -e mypy
+
+trigger-other-pipelines:
+  stage: after-tests
+  script:
+  - "if [ -z \"${TRIGGERED_FROM_OTHER_PROJECT}\" ]; then curl -X POST -F token=$CUBICWEB_PIPELINE_TRIGGER_TOKEN -F ref=branch/default https://forge.extranet.logilab.fr/api/v4/projects/385/trigger/pipeline; fi"