Update the version of kubectl to 1.3.6 to accommodate the change of saving secrets.

Author: Kenblair1226

Dockerfile

@@ -12,7 +12,7 @@ RUN ./letsencrypt-auto; exit 0
 RUN echo "OK" > /letsencrypt/challenges/.well-known/acme-challenge/health
 
 # Install kubectl
-RUN wget https://storage.googleapis.com/kubernetes-release/release/v1.2.2/bin/linux/amd64/kubectl
+RUN wget https://storage.googleapis.com/kubernetes-release/release/v1.3.6/bin/linux/amd64/kubectl
 RUN chmod +x kubectl
 RUN mv kubectl /usr/local/bin/