Fix CHANGELOG.

CHANGELOG

@@ -3,8 +3,11 @@ Please view this file on the master branch, on stable branches it's out of date.
 v 8.13.0 (unreleased)
   - Speed-up group milestones show page
 
-v 8.12.1 (unreleased)
+v 8.12.2 (unreleased)
+
+v 8.12.1
   - Fix a memory leak in HTML::Pipeline::SanitizationFilter::WHITELIST
+  - Fix issue with search filter labels not displaying
 
 v 8.12.0
   - Update the rouge gem to 2.0.6, which adds highlighting support for JSX, Prometheus, and others. !6251