[tracker/wip/carlosg/ci-pipelines: 2/7] ci: Enable detached merge request pipelines

[Carlos Garnacho <carlosg src gnome org>]

commit 3cf7b1613fb51e0558cfd3d088063f0ca55e0524
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Feb 19 10:54:39 2022 +0100

    ci: Enable detached merge request pipelines
    
    The check jobs are relying on environment variables that are only
    set on merge request pipelines, so they've been kinda ineffective
    so far.
    
    Enable the detached merge request pipelines as documented at
    https://docs.gitlab.com/ee/ci/pipelines/merge_request_pipelines.html
    so that these work. Since we want all jobs to run in merge pipelines,
    using "workflow" is good for us.

 .gitlab-ci.yml | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 0db9745f6..c62329ad4 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -23,6 +23,11 @@ stages:
   - analysis
   - website
 
+workflow:
+  rules:
+    - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
+    - if: $CI_PIPELINE_SOURCE == 'push'
+
 .check-template: &check
   extends:
     - .fdo.ci-fairy