Add bazel build for changemessage plugin 

Change-Id: I5c1c7e9f415aecbfdcf74624bbecc5bd6146480d
diff --git a/jenkins/gerrit-buck-bazel-plugin-changemessage.yaml b/jenkins/gerrit-buck-bazel-plugin-changemessage.yaml
new file mode 100644
index 0000000..d3616b1
--- /dev/null
+++ b/jenkins/gerrit-buck-bazel-plugin-changemessage.yaml
@@ -0,0 +1,6 @@
+- project:
+    name: changemessage
+    jobs:
+      - 'plugin-{name}-bazel-{branch}':
+          branch:
+            - master