feat: Change the command for testenv:releasenotes

1. change the command for testenv:releasenotes
2. add releasenotes as irrelevant-files for skyline-functional-devstack
job

Change-Id: Ia50312a136841ac42d77dcd5f23774161c9ae141

.zuul.yaml

@@ -74,6 +74,8 @@
               - ^.*\.rst$
               - ^.*\.md$
               - ^kolla/.*$
+              # releasenotes
+              - ^releasenotes/.*$
     gate:
       jobs:
         - skyline-tox-unittest-py38:
@@ -94,6 +96,8 @@
               - ^.*\.rst$
               - ^.*\.md$
               - ^kolla/.*$
+              # releasenotes
+              - ^releasenotes/.*$
     post:
       jobs:
         - publish-skyline-python-branch-tarball

tox.ini

@@ -41,6 +41,6 @@ commands =
 description =
   Generate release notes.
 commands =
-  make install
+  poetry install -vvv
   rm -rf releasenotes/build
   poetry run sphinx-build -W --keep-going -b html -j auto releasenotes/source releasenotes/build/html