Build reviewassistant plugin on stable-3.4 branch

Change-Id: I8a7c0d86f77a4e26c25afab99c28e7910fd1b5f0
diff --git a/jenkins/gerrit-bazel-plugin-reviewassistant.yaml b/jenkins/gerrit-bazel-plugin-reviewassistant.yaml
index a9ed99e..a5c3d97 100644
--- a/jenkins/gerrit-bazel-plugin-reviewassistant.yaml
+++ b/jenkins/gerrit-bazel-plugin-reviewassistant.yaml
@@ -6,6 +6,7 @@
             - master
           gerrit-branch:
             - master
+            - stable-3.4
             - stable-3.3
       - 'plugin-{name}-bazel-{branch}':
           branch: