Build websession-broker plugin on stable-3.6

Bug: Issue 15831
Change-Id: I4b472cf687215816b7f51fd0aef2cea1b8bad3ba
diff --git a/jenkins/gerrit-bazel-plugin-websession-broker.yaml b/jenkins/gerrit-bazel-plugin-websession-broker.yaml
index 31b0022..ba63b4f 100644
--- a/jenkins/gerrit-bazel-plugin-websession-broker.yaml
+++ b/jenkins/gerrit-bazel-plugin-websession-broker.yaml
@@ -6,6 +6,7 @@
             - master
           gerrit-branch:
             - master
+            - stable-3.6
             - stable-3.5
             - stable-3.4
       - 'plugin-{name}-bazel-{branch}':