Replace openstack.org git:// URLs with https://

This is a mechanically generated change to replace openstack.org
git:// URLs with https:// equivalents.

This is in aid of a planned future move of the git hosting
infrastructure to a self-hosted instance of gitea (https://gitea.io),
which does not support the git wire protocol at this stage.

This update should result in no functional change.

For more information see the thread at

 http://lists.openstack.org/pipermail/openstack-discuss/2019-March/003825.html

Change-Id: If2b913e222ef0ed323c5700de677581d91238f02
diff --git a/.zuul.yaml b/.zuul.yaml
index 4a22f54..1f05757 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -29,7 +29,7 @@
         CINDER_ISCSI_HELPER: lioadm
         TEMPEST_PLUGINS: /opt/stack/cinder-tempest-plugin
       devstack_plugins:
-        barbican: git://git.openstack.org/openstack/barbican
+        barbican: https://git.openstack.org/openstack/barbican
       devstack_services:
         barbican: true
     irrelevant-files: