docs: added release notes for 4.21.0

docs/release-notes/release-notes-4.21.0.rst

@@ -0,0 +1,54 @@
+|RCE| 4.21.0 |RNS|
+------------------
+
+Release Date
+^^^^^^^^^^^^
+
+- 2020-09-28
+
+
+New Features
+^^^^^^^^^^^^
+
+- Pull requests: overhaul of the UX/UI by adding new sidebar
+- Pull requests: new live reviewer present indicator (requires channelstream enabled)
+- Pull requests: new live new comments indicator (requires channelstream enabled)
+- Pull requests: new sidebar with comments/todos/referenced tickets navigation
+- Commits page: Introduced sidebar for single commits pages
+
+
+General
+^^^^^^^
+
+- API: allow repo admins to get/set settings.
+  Previously it was only super-admins that could do that.
+- Sessions: patch baker to take expire time for redis for auto session cleanup feature.
+- Git: bumped git version to 2.27.0
+- Packages: bumped to channelstream==0.6.14
+
+
+Security
+^^^^^^^^
+
+- Issue trackers: fix XSS with description field.
+
+
+Performance
+^^^^^^^^^^^
+
+- Artifacts: speed-up of artifacts download request processing.
+
+
+Fixes
+^^^^^
+
+- Pull requests: properly save merge failure metadata.
+  In rare cases merge check reported conflicts which there were none.
+- Sessions: fixed cleanup with corrupted session data issue.
+
+
+Upgrade notes
+^^^^^^^^^^^^^
+
+- Scheduled feature release.
+- Git version was bumped to 2.27.0

docs/release-notes/release-notes.rst

@@ -9,6 +9,7 @@ Release Notes
 .. toctree::
    :maxdepth: 1
 
+   release-notes-4.21.0.rst
    release-notes-4.20.1.rst
    release-notes-4.20.0.rst
    release-notes-4.19.3.rst