Document "skip build" label

docs/automatic-manifest-integration.md

@@ -110,6 +110,15 @@ full manifest environment **before merging them**. Actually we even prevent the
 project merge requests from being merged unless the pipeline has run
 successfully.
 
+#### Skipping the build
+
+In the case of changes that are not build-relevant or have a rather low
+probability of breaking the build (for example documentation), the developer has
+the option to skip the build by adding the `skip build` label to a merge request
+on its creation. The `build` and `check` stages of the pipeline are left out
+then, and the merge request can be merged immediately after the `integrate`
+stage has completed.
+
 [4]: https://docs.gitlab.com/ee/ci/pipelines/multi_project_pipelines.html
 [5]: #merging-project-changes
 [6]: https://git.seco.com/seco-ne/yocto/layers/meta-seconorth-distro/-/merge_requests/321