Build uploadvalidator plugin on stable-3.4

Change-Id: Icd6960a51b3d36dcaeed6a38b851626130c74eab
diff --git a/jenkins/gerrit-bazel-plugin-uploadvalidator.yaml b/jenkins/gerrit-bazel-plugin-uploadvalidator.yaml
index c1cb8f7..c035125 100644
--- a/jenkins/gerrit-bazel-plugin-uploadvalidator.yaml
+++ b/jenkins/gerrit-bazel-plugin-uploadvalidator.yaml
@@ -1,6 +1,11 @@
 - project:
     name: uploadvalidator
     jobs:
+      - 'plugin-{name}-bazel-{branch}-{gerrit-branch}':
+          branch:
+            - master
+          gerrit-branch:
+            - stable-3.4
       - 'plugin-{name}-bazel-{branch}':
           branch:
             - master