Update CHANGELOG for 8.10.5

Signed-off-by: Rémy Coutable <remy@rymai.me>

CHANGELOG

@@ -90,8 +90,10 @@ v 8.11.0 (unreleased)
   - Fix importing GitLab projects with an invalid MR source project
   - Sort folders with submodules in Files view !5521
 
-v 8.10.5 (unreleased)
-  - Cache project count for 5 minutes to reduce DB load
+v 8.10.5
+  - Add a data migration to fix some missing timestamps in the members table. !5670
+  - Revert the "Defend against 'Host' header injection" change in the source NGINX templates. !5706
+  - Cache project count for 5 minutes to reduce DB load. !5746 & !5754
 
 v 8.10.4
   - Don't close referenced upstream issues from a forked project.