Set kubectl version to 1.11.7

Author: Pavle Predic

Dockerfile

@@ -1,5 +1,5 @@
 FROM alpine:3.8
-ARG KUBECTL_VERSION=1.9.1
+ARG KUBECTL_VERSION=1.11.7
 RUN apk add --update python python-dev py-pip build-base curl bash vim jq git openssl-dev libffi-dev gettext bind-tools
 RUN curl -o /usr/local/bin/kubectl "https://storage.googleapis.com/kubernetes-release/release/v$KUBECTL_VERSION/bin/linux/amd64/kubectl" && \
     chmod +x /usr/local/bin/kubectl && \