docs: added changelog for 4.12.3 release

docs/release-notes/release-notes-4.12.3.rst

@@ -0,0 +1,57 @@
+|RCE| 4.12.3 |RNS|
+------------------
+
+Release Date
+^^^^^^^^^^^^
+
+- 2018-06-18
+
+
+New Features
+^^^^^^^^^^^^
+
+
+
+General
+^^^^^^^
+
+- Git: set GIT_DISCOVERY_ACROSS_FILESYSTEM flag for better compatibility,
+  and error tracking on mounted drives.
+
+
+Security
+^^^^^^^^
+
+- Git: Upgraded GIT version to 2.16.4 to address security problems
+  in earlier versions.
+
+
+Performance
+^^^^^^^^^^^
+
+
+
+Fixes
+^^^^^
+
+- Caches: fix beaker sqlalchemy options propagation. This should fix some of the
+  MySQL problems ("MySQL has gone away") reported with db cache backend.
+- Shadow repos: use safer way to delete shadow repositories. Use the same
+  mechanism as deleting repositories for shadow repos too. This tries to
+  address problems on failed removal of shadow repositories that cause
+  later problems.
+- Pull requests: solve an issue with long database transaction row locking for
+  large pull requests. Mysql backend row locking caused access problem to the
+  server during time a large PR was beeing created. This is now solved by
+  smarter DB transaction management.
+- SVN: Fixed misleading errors when SSL was force enabled byt users used
+  plain HTTP. Now we report proper errors instead of missing header error
+  caused by a bug.
+
+
+Upgrade notes
+^^^^^^^^^^^^^
+
+- Scheduled release addressing reported GIT client security problem,
+  and some reported bugs.
+

docs/release-notes/release-notes.rst

@@ -9,6 +9,7 @@ Release Notes
 .. toctree::
    :maxdepth: 1
 
+   release-notes-4.12.3.rst
    release-notes-4.12.2.rst
    release-notes-4.12.1.rst
    release-notes-4.12.0.rst