ci: Open issues when scheduled pipelines fails

It's hard to track failures on scheduled pipelines, so make gitlab open
an issue for us if that happens.

.gitlab-ci.yml

@@ -4,6 +4,7 @@ stages:
   - coverage
   - analysis
   - deploy
+  - report
 
 cache:
   paths:
@@ -594,3 +595,11 @@ dist-job:
       - "${CI_PROJECT_DIR}/_build/gobject-docs-$CI_COMMIT_TAG.tar.xz"
       - "${CI_PROJECT_DIR}/_build/gio-docs-$CI_COMMIT_TAG.tar.xz"
       - "${CI_PROJECT_DIR}/_build/meson-dist/glib-*.tar.xz"
+
+issue-bot:
+  stage: report
+  image: registry.gitlab.com/gitlab-org/distribution/issue-bot:latest
+  script: /issue-bot
+  rules:
+    - if: $CI_COMMIT_REF_NAME == $CI_DEFAULT_BRANCH && $CI_PIPELINE_SOURCE == "schedule"
+      when: on_failure