Build branch-network against gerrit stable-3.6

Bug: Issue 15831
Change-Id: I1a8ebbd6056080147250792b453b6150679e2cb5
diff --git a/jenkins/gerrit-bazel-plugin-branch-network.yaml b/jenkins/gerrit-bazel-plugin-branch-network.yaml
index 9302fba..fad5365 100644
--- a/jenkins/gerrit-bazel-plugin-branch-network.yaml
+++ b/jenkins/gerrit-bazel-plugin-branch-network.yaml
@@ -5,6 +5,7 @@
           branch:
             - master
           gerrit-branch:
+            - stable-3.6
             - stable-3.5
             - stable-3.4
             - stable-3.3