apertis_packaging_guide: Reflect usage of the external CI config

We no longer use the `debian/apertis/gitlab-ci.yml` files in each
packaging repository but rather rely on a external CI config path.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

content/guides/apertis_packaging_guide.md

@@ -7,8 +7,9 @@ title = "Apertis Development Guide"
 
 # Apertis Packaging CI
 
-Apertis stores the source of all the shipped packages in GitLab and uses a set
-of GitLab CI pipelines to manage the workflows to:
+Apertis stores the source of all the shipped packages in GitLab and uses a
+[GitLab CI pipeline](https://gitlab.apertis.org/infrastructure/ci-package-builder/-/blob/master/ci-package-builder.yml)
+to manage the workflows to:
 
 * land updated sources to OBS which will then build the binary outputs
 * pull updates from upstream distributions like Debian 10 Buster
@@ -225,7 +226,7 @@ This is the process to import a new package from Debian to Apertis:
 * push your local git contents to the newly created GitLab project: `git push --all --follow-tags origin`
 * set it up with `gitlab-rulez apply rulez.yaml --filter pkg/hello` from
   the [gitlab-rulez repository](https://gitlab.apertis.org/infrastructure/gitlab-rulez)
-  * sets the CI config path to `debian/apertis/gitlab-ci.yml`
+  * sets the CI config path to `ci-package-builder.yml@infrastructure/ci-package-builder`
   * changes the merge request settings:
       * only allow fast-forward merges
       * ensure merges are only allowed if pipelines succeed
@@ -420,8 +421,6 @@ under `debian/apertis/copyright`, updating the merge request when necessary.
 Main components:
 * [`ci-package-builder`](https://gitlab.apertis.org/infrastructure/ci-package-builder):
   centralized location of the GitLab-to-OBS and Debian-to-GitLab pipeline definitions
-* [`debian/apertis/gitlab-ci.yaml`](https://gitlab.apertis.org/pkg/target/base-files/blob/apertis/v2019/debian/apertis/gitlab-ci.yml):
-  imports the `ci-package-builder` pipelines from each packaging repository
 * [`apertis-package-source-builder`](https://gitlab.apertis.org/infrastructure/apertis-docker-images/tree/apertis/v2019/apertis-package-source-builder):
   Docker environment for the GitLab pipelines
 * [`pristine-lfs`](https://salsa.debian.org/andrewsh/pristine-lfs): stores