Deprecation notice for package pipeline pagination

data/deprecations/15-0-remove-package-pipelines-api.yml

+- name: "Package pipelines in API payload is paginated" # The name of the feature to be deprecated
+  announcement_milestone: "14.5" # The milestone when this feature was first announced as deprecated.
+  announcement_date: "2021-11-22" # The date of the milestone release when this feature was first announced as deprecated. This should almost always be the 22nd of a month (YYYY-MM-22), unless you did an out of band blog post.
+  removal_milestone: "15.0" # The milestone when this feature is planned to be removed
+  body: | # Do not modify this line, instead modify the lines below.
+    A request to the API for `/api/v4/projects/:id/packages` returns a paginated result of packages. Each package lists all of its pipelines in this response. This is a performance concern, as it's possible for a package to have hundreds or thousands of associated pipelines.
+
+    In milestone 15.0, we will remove the `pipelines` attribute from the API response.
+  stage: package
+  tiers: Free
+  issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/289956

doc/update/deprecations.md

@@ -102,6 +102,14 @@ Note that we are not deprecating the Kerberos SPNEGO integration, only the old p
 
 Announced: 2021-09-22
 
+### Package pipelines in API payload is paginated
+
+A request to the API for `/api/v4/projects/:id/packages` returns a paginated result of packages. Each package lists all of its pipelines in this response. This is a performance concern, as it's possible for a package to have hundreds or thousands of associated pipelines.
+
+In milestone 15.0, we will remove the `pipelines` attribute from the API response.
+
+Announced: 2021-11-22
+
 ### REST API Runner will not contain `paused`
 
 Runner REST API will not return `paused` as a status in GitLab 15.0.