ci: Document a new cache and a new stage

Signed-off-by: Rémy Coutable <remy@rymai.me>

doc/development/pipelines.md

@@ -497,18 +497,20 @@ request, be sure to start the `dont-interrupt-me` job before pushing.
 1. We currently have several different caches defined in
    [`.gitlab/ci/global.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/global.gitlab-ci.yml),
    with fixed keys:
-   - `.setup-test-env-cache`.
-   - `.rails-cache`.
-   - `.static-analysis-cache`.
+   - `.setup-test-env-cache`
+   - `.rails-cache`
+   - `.static-analysis-cache`
    - `.coverage-cache`
+   - `.danger-review-cache`
    - `.qa-cache`
-   - `.yarn-cache`.
+   - `.yarn-cache`
    - `.assets-compile-cache` (the key includes `${NODE_ENV}` so it's actually two different caches).
 1. Only 6 specific jobs, running in 2-hourly scheduled pipelines, are pushing (i.e. updating) to the caches:
    - `update-setup-test-env-cache`, defined in [`.gitlab/ci/rails.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/rails.gitlab-ci.yml).
    - `update-rails-cache`, defined in [`.gitlab/ci/rails.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/rails.gitlab-ci.yml).
    - `update-static-analysis-cache`, defined in [`.gitlab/ci/rails.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/rails.gitlab-ci.yml).
    - `update-coverage-cache`, defined in [`.gitlab/ci/rails.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/rails.gitlab-ci.yml).
+   - `update-danger-review-cache`, defined in [`.gitlab/ci/review.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/review.gitlab-ci.yml).
    - `update-qa-cache`, defined in [`.gitlab/ci/qa.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/qa.gitlab-ci.yml).
    - `update-assets-compile-production-cache`, defined in [`.gitlab/ci/frontend.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/frontend.gitlab-ci.yml).
    - `update-assets-compile-test-cache`, defined in [`.gitlab/ci/frontend.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/frontend.gitlab-ci.yml).
@@ -614,6 +616,7 @@ that is deployed in stage `review`.
   [`coverage-javascript`](https://gitlab-org.gitlab.io/gitlab/coverage-javascript/),
   and `webpack-report` (found at `https://gitlab-org.gitlab.io/gitlab/webpack-report/`, but there is
   [an issue with the deployment](https://gitlab.com/gitlab-org/gitlab/-/issues/233458)).
+- `notify`: This stage includes jobs that notify various failures to Slack.
 
 ### Default image