CI: Add linting to releasenotes

Change-Id: Ia1237f1366379aa23666c1665bc046db4c34d671

tox.ini

@@ -50,17 +50,29 @@ skip_install = true
 commands =
   rm -rf doc/build
   doc8 doc
+  reno lint
+  doc8 -e '.yaml' releasenotes/notes/
   sphinx-build -W --keep-going -b html doc/source doc/build/html
 allowlist_externals = rm
 
 [testenv:releasenotes]
 deps = {[testenv:docs]deps}
 commands =
+  reno lint
+  doc8 -e '.yaml' releasenotes/notes/
   sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:debug]
 commands = oslo_debug_helper {posargs}
 
+[doc8]
+# Skip old releasenotes that don't pass checks
+ignore-path =
+  releasenotes/notes/initial-release-f507ed074fcf7763.yaml,
+  releasenotes/notes/autoscaling-default-worker-group-751f100603fb3d0a.yaml,
+  releasenotes/notes/autoscaling-all-worker-groups-8c7a07d0f56ac2ca.yaml,
+  releasenotes/notes/change-helm-repo-55869552914bb9ed.yaml
+
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.
 
@@ -68,3 +80,4 @@ show-source = True
 ignore = E123,E125
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
+