Build owners for Gerrit v2.16 on its own branch

Owners plugin for v2.16 and v3.0/master are now diverging
and need to be build on their own branches.

Change-Id: I4188b26eaa61a0b01f67b7d6032346a6d09909f3
diff --git a/jenkins/gerrit-buck-bazel-plugin-owners.yaml b/jenkins/gerrit-buck-bazel-plugin-owners.yaml
index 7b80035..35bf805 100644
--- a/jenkins/gerrit-buck-bazel-plugin-owners.yaml
+++ b/jenkins/gerrit-buck-bazel-plugin-owners.yaml
@@ -53,6 +53,7 @@
       - 'plugin-owners-bazel-{branch}':
           targets: 'plugins/owners plugins/owners-autoassign'
           branch:
+            - stable-2.16
             - stable-2.15
             - stable-2.14
       - 'plugin-owners-bazel-{branch}-{gerrit-branch}':
@@ -62,4 +63,3 @@
           gerrit-branch:
             - master
             - stable-3.0
-            - stable-2.16