Add deprecation notice for fixup commit messages

fixup

data/deprecations/14-8-remove-support-for-fixup-in-commit-message-triggering-draft-status.yml

+- name: "`fixup!` commit messages setting draft status of associated Merge Request" # The name of the feature to be deprecated
+  announcement_milestone: "14.8" # The milestone when this feature was first announced as deprecated.
+  announcement_date: "2022-02-22" # 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
+  removal_date: "2022-06-22" # This should almost always be the 22nd of a month (YYYY-MM-22), the date of the milestone release when this feature is planned to be removed.
+  body: | # Do not modify this line, instead modify the lines below.
+    The use of `fixup!` as a commit message to trigger draft status
+    of the associated Merge Request is generally unused, and can cause
+    confusion with other uses of the term. "Draft" is the preferred
+    and supported trigger for triggering draft status from commit
+    messages, as part of our streamlining of the feature.
+    Support for `fixup!` is now considered deprecated, and will be
+    removed in GitLab 15.0.
+  documentation_url: "https://docs.gitlab.com/ee/user/project/merge_requests/drafts.html#mark-merge-requests-as-drafts"
+  issue_url: "https://gitlab.com/gitlab-org/gitlab/-/issues/342937"

doc/update/deprecations.md

@@ -702,3 +702,17 @@ Tracing in GitLab is an integration with Jaeger, an open-source end-to-end distr
 The `merged_by` field in the [merge request API](https://docs.gitlab.com/ee/api/merge_requests.html#list-merge-requests) is being deprecated and will be removed in GitLab 15.0. This field is being replaced with the `merge_user` field (already present in GraphQL) which more correctly identifies who merged a merge request when performing actions (merge when pipeline succeeds, add to merge train) other than a simple merge.
 
 **Planned removal milestone: 15.0 ()**
+
+## 14.8
+
+### `fixup!` commit messages setting draft status of associated Merge Request
+
+The use of `fixup!` as a commit message to trigger draft status
+of the associated Merge Request is generally unused, and can cause
+confusion with other uses of the term. "Draft" is the preferred
+and supported trigger for triggering draft status from commit
+messages, as part of our streamlining of the feature.
+Support for `fixup!` is now considered deprecated, and will be
+removed in GitLab 15.0.
+
+**Planned removal milestone: 15.0 (2022-06-22)**