ci: Apply GNOME templates default rules

Re-use rules from https://gitlab.gnome.org/GNOME/citemplates/ default-rules
template, but without importing them to ensure that changes in the
citemplates project won't affect us directly

So we have some basic control on what should trigger a workflow,
auto-retry and auto-replace on subsequent pushes

.gitlab-ci.yml

@@ -4,6 +4,26 @@ include:
       dist-job-name: "dist-job"
       tarball-artifact-path: "${TARBALL_ARTIFACT_PATH}"
 
+# This is based on GNOME/citemplates default-rules, but we only apply the
+# settings that make sense for glib
+default:
+  interruptible: true
+  # Auto-retry jobs in case of infra failures
+  retry:
+    max: 1
+    when:
+      - "runner_system_failure"
+      - "stuck_or_timeout_failure"
+      - "scheduler_failure"
+      - "api_failure"
+
+workflow:
+  rules:
+    - if: $CI_PIPELINE_SOURCE == "web"
+    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
+    - if: $CI_COMMIT_TAG
+    - if: $CI_COMMIT_BRANCH
+
 stages:
   - style-check
   - build