[damned-lies] ci: do not run job when committing po files

[Claude Paroz <claudep src gnome org>]

commit 18a2b94ab7f83dc4cb4ffefec0002b2dfe22f583
Author: Guillaume Bernard <associations guillaume-bernard fr>
Date:   Mon Apr 19 22:06:00 2021 +0200

    ci: do not run job when committing po files

 .gitlab-ci.yml | 11 +++++++++++
 1 file changed, 11 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 622755a6..0a4b415a 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -17,4 +17,15 @@ test:
     expire_in: 2 days
     reports:
       cobertura: coverage.xml
+  rules:
+    # When job is triggered after a push event, run only when code files changed
+    - if: $CI_PIPELINE_SOURCE == "push"
+      changes:
+        - po/*  # po files are committed by l10n itself
+        - docs/*
+        - "*.md"
+      when: manual
+    # Otherwise, always run job.
+    - when: always
+      allow_failure: false