Announce deprecation of `external` field in Releases/Release Links APIs

data/deprecations/15-9-deprecate-external-field-in-releases-and-release-links-apis.yml

+- title: "External field in Releases and Release Links APIs"
+  announcement_milestone: "15.9"
+  announcement_date: "2023-02-22"
+  removal_milestone: "16.0"
+  removal_date: "2023-05-22"
+  breaking_change: true
+  reporter: ahmed.hemdan
+  body: |
+    In [Releases API](https://docs.gitlab.com/ee/api/releases) and [Release Links API](https://docs.gitlab.com/ee/api/releases/links.html), the `external` field was used to indicate whether a [release link](https://docs.gitlab.com/ee/user/project/releases/release_fields.html#links) is internal or external to your GitLab instance.
+    As of GitLab 15.9, we treat all release links as external, and therefore, this field is deprecated in GitLab 15.9, and will be removed in GitLab 16.0.
+    To avoid any disruptions to your workflow, please stop using the `external` field because it will be removed and will not be replaced.
+  stage: Release
+  issue_url:

doc/update/deprecations.md

@@ -159,6 +159,22 @@ During the transition to the GitLab Observability UI, we will migrate the [GitLa
 </div>
+<div class="deprecation removal-160 breaking-change">
+
+### External field in Releases and Release Links APIs
+
+Planned removal: GitLab <span class="removal-milestone">16.0</span> <span class="removal-date"></span>
+
+WARNING:
+This is a [breaking change](https://docs.gitlab.com/ee/development/deprecation_guidelines/).
+Review the details carefully before upgrading.
+
+In [Releases API](https://docs.gitlab.com/ee/api/releases) and [Release Links API](https://docs.gitlab.com/ee/api/releases/links.html), the `external` field was used to indicate whether a [release link](https://docs.gitlab.com/ee/user/project/releases/release_fields.html#links) is internal or external to your GitLab instance.
+As of GitLab 15.9, we treat all release links as external, and therefore, this field is deprecated in GitLab 15.9, and will be removed in GitLab 16.0.
+To avoid any disruptions to your workflow, please stop using the `external` field because it will be removed and will not be replaced.
+
+</div>
+
 <div class="deprecation removal-170 breaking-change">
 ### Filepath field in Releases and Release Links APIs