Distribution 14.9 Deprecation notice

data/deprecations/14-9-deprecate-debian-9.yml

+- name: "Deprecate support for Debian 9"
+  announcement_milestone: "14.9"
+  announcement_date: "2022-03-22"
+  removal_milestone: "15.1"
+  removal_date: "2022-06-22"
+  body: |
+    Long term service and support (LTSS) for [Debian 9 Stretch ends in July 2022](https://wiki.debian.org/LTS). Therefore, we will longer support the Debian 9 distribution for the GitLab package. Users can upgrade to Debian 10 or Debian 11.

doc/update/deprecations.md

@@ -38,6 +38,12 @@ For deprecation reviewers (Technical Writers only):
 
 ## 14.9
 
+### Deprecate support for Debian 9
+
+Long term service and support (LTSS) for [Debian 9 Stretch ends in July 2022](https://wiki.debian.org/LTS). Therefore, we will longer support the Debian 9 distribution for the GitLab package. Users can upgrade to Debian 10 or Debian 11.
+
+**Planned removal milestone: 15.1 (2022-06-22)**
+
 ### GitLab Pages running as daemon
 
 In 15.0, support for daemon mode for GitLab Pages will be removed.