Bump OVN version for master jobs

This patch bumps the version currently used in master jobs to
the latest release v21.06.0.

Signed-off-by: Daniel Alvarez Sanchez <dalvarez@redhat.com>
Change-Id: I679108aab8c17e2cbd8d64388f9d0b1420a1323c
diff --git a/zuul.d/master_jobs.yaml b/zuul.d/master_jobs.yaml
index 063eb02..f6781b1 100644
--- a/zuul.d/master_jobs.yaml
+++ b/zuul.d/master_jobs.yaml
@@ -386,7 +386,7 @@
         # TODO(eolivare): Remove OVN_BUILD_FROM_SOURCE once vlan-transparency
         # is included in an ovn released version
         OVN_BUILD_FROM_SOURCE: True
-        OVN_BRANCH: "v20.12.0"
+        OVN_BRANCH: "v21.06.0"
         OVS_BRANCH: "branch-2.15"
         OVS_SYSCONFDIR: "/usr/local/etc/openvswitch"
       devstack_services: