add hard stop for 25.5.1

Author: hubertdeng123

develop-docs/self-hosted/releases.mdx

@@ -53,6 +53,7 @@ These are the hard stops that one needs to go through:
 - 23.6.2 (execute `COMPOSE_PROJECT_NAME=sentry_onpremise docker compose down --rmi local --remove-orphans` before you upgrade to > 21.12.0)
 - 23.11.0
 - 24.8.0
+- 25.5.1
 
 Versions to avoid upgrading to:
 - 23.7.0 (issues around database migrations and the Django 3 upgrade)