Move release doc to our operations playbook. (#614)

This moves our release operations to live alongside the rest of our
release
docs.

- readthedocs/readthedocs-ops#1670

Author: agjohnson

CHANGELOG.rst

@@ -1,7 +1,11 @@
 CHANGELOG
 =========
 
-.. The text for the changelog is manually generated for now.
+.. note::
+   This repository has moved to using releases on GitHub. The versions documented here
+   are historical and won't be reflected in the release changelog.
+
+   `See the latest releases <https://github.com/readthedocs/addons/releases>`_
 
 Version 0.36.0
 --------------

docs/changelog.rst

@@ -67,14 +67,8 @@ Contents
 
 .. toctree::
 
-   releasing
    testing
 
-.. toctree::
-   :maxdepth: 1
-
-   Changelog <changelog>
-
 .. raw:: html
 
     <style>