Update CHANGELOG.md for 8.13.7

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CHANGELOG.md

 Please view this file on the master branch, on stable branches it's out of date.
 
+## 8.13.7 (2016-11-28)
+
+- fixes 500 error on project show when user is not logged in and project is still empty. !7376
+- Update grape entity to 0.6.0. !7491
+- Fix information disclosure in `Projects::BlobController#update`.
+- Fix missing access checks on issue lookup using IssuableFinder.
+- Replace issue access checks with use of IssuableFinder.
+- Non members cannot create labels through the API.
+
 ## 8.13.6 (2016-11-17)
 
 - Omniauth auto link LDAP user falls back to find by DN when user cannot be found by UID. !7002

changelogs/unreleased/23990-project-show-error-when-empty-repo.yml

----
-title: fixes 500 error on project show when user is not logged in and project is still empty
-merge_request: 7376
-author: 

changelogs/unreleased/jej-22869.yml

----
-title: 'Fix information disclosure in `Projects::BlobController#update`'
-merge_request:
-author:

changelogs/unreleased/jej-fix-missing-access-check-on-issues.yml

----
-title: Fix missing access checks on issue lookup using IssuableFinder
-merge_request: 
-author: 

changelogs/unreleased/jej-use-issuable-finder-instead-of-access-check.yml

----
-title: Replace issue access checks with use of IssuableFinder
-merge_request: 
-author: 

changelogs/unreleased/zj-fix-label-creation-non-members.yml

----
-title: Non members cannot create labels through the API
-merge_request: 
-author: 

changelogs/unreleased/zj-upgrade-grape.yml

----
-title: Update grape entity to 0.6.0
-merge_request: 7491
-author: