Add reno for release notes management

Change-Id: I81337ca27fa639da74cb34a874fbbc6248026c34

tox.ini

@@ -46,7 +46,7 @@ commands =
 show-source=True
 ignore=
 builtins= _
-exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build,*sqlalchemy/alembic/versions/*,demo/
+exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build,*sqlalchemy/alembic/versions/*,demo/,releasenotes
 
 [testenv:wheel]
 commands = python setup.py bdist_wheel
@@ -58,3 +58,6 @@ import_exceptions = watcher._i18n
 extension=.rst
 # todo: stop ignoring doc/source/man when https://bugs.launchpad.net/doc8/+bug/1502391 is fixed
 ignore-path=doc/source/image_src,doc/source/man,doc/source/api
+
+[testenv:releasenotes]
+commands = sphinx-build -a -W -E -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html