update changelog

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
+v 7.13.4
+  - Allow users to send abuse reports
+
 v 7.13.3
   - Fix bug causing Bitbucket importer to crash when OAuth application had been removed.
-  - Add fetch command to the MR page.
-  - Add ability to manage user email addresses via the API.
-  - Show buttons to add license, changelog and contribution guide if they're missing.
-  - Tweak project page buttons.
-  - Disabled autocapitalize and autocorrect on login field (Daryl Chan)
-  - Mention group and project name in creation, update and deletion notices (Achilleas Pipinellis)
-  - Remove redis-store TTL monkey patch
-  - Add support for CI skipped status
-  - Fetch code from forks to refs/merge-requests/:id/head when merge request created
-  - Remove satellites 
-  - Allow users to send abuse reports
 
 v 7.13.2
   - Fix randomly failed spec