Add 8.6.6 CHANGELOG entries

[ci skip]
Signed-off-by: NRémy Coutable <remy@rymai.me>

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.7.0 (unreleased)
-  - The Projects::HousekeepingService class has extra instrumentation (Yorick Peterse)
-  - Fix revoking of authorized OAuth applications (Connor Shea)
-  - All service classes (those residing in app/services) are now instrumented (Yorick Peterse)
-  - Developers can now add custom tags to transactions (Yorick Peterse)
-  - Loading of an issue's referenced merge requests and related branches is now done asynchronously (Yorick Peterse)
+  - The Projects::HousekeepingService class has extra instrumentation
+  - All service classes (those residing in app/services) are now instrumented
+  - Developers can now add custom tags to transactions
+  - Loading of an issue's referenced merge requests and related branches is now done asynchronously
   - Enable gzip for assets, makes the page size significantly smaller. !3544 / !3632 (Connor Shea)
+  - Project switcher uses new dropdown styling
   - Load award emoji images separately unless opening the full picker. Saves several hundred KBs of data for most pages. (Connor Shea)
   - Do not include award_emojis in issue and merge_request comment_count !3610 (Lucas Charles)
   - All images in discussions and wikis now link to their source files !3464 (Connor Shea).
@@ -14,7 +14,7 @@ v 8.7.0 (unreleased)
   - Add setting for customizing the list of trusted proxies !3524
   - Allow projects to be transfered to a lower visibility level group
   - Fix `signed_in_ip` being set to 127.0.0.1 when using a reverse proxy !3524
-  - Improved Markdown rendering performance !3389 (Yorick Peterse)
+  - Improved Markdown rendering performance !3389
   - Don't attempt to look up an avatar in repo if repo directory does not exist (Stan Hu)
   - API: Ability to subscribe and unsubscribe from issues and merge requests (Robert Schilling)
   - Expose project badges in project settings
@@ -75,8 +75,9 @@ v 8.7.0 (unreleased)
   - Fix emoji catgories in the emoji picker
 
 v 8.6.6
-  - Fix error on language detection when repository has no HEAD (e.g., master branch). !3654 (Jeroen Bobbeldijk)
-  - Project switcher uses new dropdown styling
+  - Expire the exists cache before deletion to ensure project dir actually exists (Stan Hu). !3413
+  - Fix error on language detection when repository has no HEAD (e.g., master branch) (Jeroen Bobbeldijk). !3654
+  - Fix revoking of authorized OAuth applications (Connor Shea). !3690
 
 v 8.6.5
   - Fix importing from GitHub Enterprise. !3529
@@ -276,7 +277,7 @@ v 8.5.1
 
 v 8.5.0
   - Fix duplicate "me" in tooltip of the "thumbsup" awards Emoji (Stan Hu)
-  - Cache various Repository methods to improve performance (Yorick Peterse)
+  - Cache various Repository methods to improve performance
   - Fix duplicated branch creation/deletion Webhooks/service notifications when using Web UI (Stan Hu)
   - Ensure rake tasks that don't need a DB connection can be run without one
   - Update New Relic gem to 3.14.1.311 (Stan Hu)