Build saml plugin on stable-3.4 branch

Change-Id: I0fadad345b792570a042f87f619de5364ba14b4f
diff --git a/jenkins/gerrit-plugin-saml.yaml b/jenkins/gerrit-plugin-saml.yaml
index b7a03ec..6caafff 100644
--- a/jenkins/gerrit-plugin-saml.yaml
+++ b/jenkins/gerrit-plugin-saml.yaml
@@ -8,3 +8,8 @@
             - stable-3.2
             - stable-3.1
             - stable-2.16
+      - 'plugin-{name}-bazel-{branch}-{gerrit-branch}':
+          branch:
+            - master
+          gerrit-branch:
+            - stable-3.4