Update latest stable branch to 3.6

Change-Id: Ia8803dcdd3400d18000246755bb1f47c8cb7c774
diff --git a/jenkins-docker/agent-bazel/Dockerfile b/jenkins-docker/agent-bazel/Dockerfile
index cbcbdd5..3ec12ba 100644
--- a/jenkins-docker/agent-bazel/Dockerfile
+++ b/jenkins-docker/agent-bazel/Dockerfile
@@ -3,7 +3,7 @@
 # Bazel cache warm-up with Gerrit master and latest stable branch.
 # Set-up google-java-format utility to ~/format/google-java-format.
 USER jenkins
-RUN bash -c 'cd /tmp && git clone -b stable-3.5 --recursive https://gerrit.googlesource.com/gerrit && \
+RUN bash -c 'cd /tmp && git clone -b stable-3.6 --recursive https://gerrit.googlesource.com/gerrit && \
     cd /tmp/gerrit && \
     ./tools/setup_gjf.sh 1.7 && \
     ( bazelisk build --remote_cache=https://gerrit-ci.gerritforge.com/cache --noremote_upload_local_results plugins:core release api || true ) && \