Add 8.0.0 entry to CHANGELOG-EE

Make 7.13.3 entry style consistent with others

CHANGELOG-EE

-v 7.14
+v 8.0.0 (unreleased)
+
+v 7.14.0
   - Disable adding, updating and removing members from a group that is synced with LDAP
   - Don't send "Added to group" notifications when group is LDAP synched
   - Fix importing projects from GitHub Enterprise Edition.
@@ -7,7 +9,7 @@ v 7.14
   - Automatic approver suggestions (based on an authority of the code)  
   - Support Kerberos ticket-based authentication for Git HTTP access
 
-v7.13.3
+v 7.13.3
   - Merge community edition changes for version 7.13.3
   - Improved validation for an approver
   - Don't resend admin email to everyone if one delivery fails