Add simple liaisons wrapper module

I'm going to want to use this in a later change so lets make the
abstraction now

Change-Id: I0d15b5137d857bffb2bed39e995e50fed24f5598

openstack_releases/cmds/list_changes.py

@@ -29,7 +29,6 @@ import shutil
 import subprocess
 import sys
 import tempfile
-import yaml
 
 from openstack_governance import governance
 import pyfiglet
@@ -39,6 +38,7 @@ from openstack_releases import defaults
 from openstack_releases import deliverable
 from openstack_releases import gitutils
 from openstack_releases import hound
+from openstack_releases import liaisons
 from openstack_releases import release_notes
 from openstack_releases import yamlutils
 
@@ -260,8 +260,7 @@ def main():
         False,
     )
 
-    with open("./data/release_liaisons.yaml", "r") as f:
-        liaison_data = yaml.safe_load(f)
+    liaison_data = liaisons.get_liaisons()
 
     # Remove any inherited PAGER environment variable to avoid
     # blocking the output waiting for input.

openstack_releases/liaisons.py

@@ -0,0 +1,23 @@
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""Simple wrapper(s) around liaison data"""
+
+import yaml
+
+
+def get_liaisons():
+    with open("./data/release_liaisons.yaml", "r") as f:
+        liaison_data = yaml.safe_load(f)
+    return liaison_data