Build audit-sl4j plugin on stable-3.6

Bug: Issue 15831
Change-Id: I616642d3de9b7a8f9f6cfb10bae15b4a82bf8916
diff --git a/jenkins/gerrit-bazel-plugin-audit-sl4j.yaml b/jenkins/gerrit-bazel-plugin-audit-sl4j.yaml
index 6a13f42..57fd61f 100644
--- a/jenkins/gerrit-bazel-plugin-audit-sl4j.yaml
+++ b/jenkins/gerrit-bazel-plugin-audit-sl4j.yaml
@@ -9,5 +9,6 @@
           branch:
             - master
           gerrit-branch:
+            - stable-3.6
             - stable-3.5
             - stable-3.4