Update versions (argoproj#1218)

Dockerfile

@@ -3,7 +3,7 @@
 # Initial stage which pulls prepares build dependencies and CLI tooling we need for our final image
 # Also used as the image in CI jobs so needs all dependencies
 ####################################################################################################
-FROM golang:1.11.4 as builder
+FROM golang:1.11.5 as builder
 
 RUN apt-get update && apt-get install -y \
  git \
@@ -41,7 +41,7 @@ RUN curl -sLo- https://github.com/alecthomas/gometalinter/releases/download/v${G
 ####################################################################################################
 FROM debian:9.6-slim as argoexec-base
 # NOTE: keep the version synced with https://storage.googleapis.com/kubernetes-release/release/stable.txt
-ENV KUBECTL_VERSION=1.13.1
+ENV KUBECTL_VERSION=1.13.4
 RUN apt-get update && \
  apt-get install -y curl jq procps git tar mime-support && \
  rm -rf /var/lib/apt/lists/* && \