Build plugin-manager for Gerrit 2.14

Change-Id: Ib309ab785c1f9e76e84e96e2a3ff751583c2a798
diff --git a/jenkins/gerrit-buck-bazel-plugin-plugin-manager.yaml b/jenkins/gerrit-buck-bazel-plugin-plugin-manager.yaml
index a92ad61..8b1e5ef 100644
--- a/jenkins/gerrit-buck-bazel-plugin-plugin-manager.yaml
+++ b/jenkins/gerrit-buck-bazel-plugin-plugin-manager.yaml
@@ -6,4 +6,5 @@
             - stable-2.13
       - 'plugin-{name}-bazel-{branch}':
           branch:
+            - stable-2.14
             - master