Bump go 1.16.6 (addresses CVE-2021-34558)

This addresses CVE-2021-34558: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-34558

go1.16.6 (released 2021-07-12) includes a security fix to the crypto/tls package,
as well as bug fixes to the compiler, and the net and net/http packages. See the
Go 1.16.6 milestone on the issue tracker for details:

https://github.com/golang/go/issues?q=milestone%3AGo1.16.6+label%3ACherryPickApproved

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Dockerfile

@@ -3,7 +3,7 @@
 ARG CROSS="false"
 ARG SYSTEMD="false"
 # IMPORTANT: When updating this please note that stdlib archive/tar pkg is vendored
-ARG GO_VERSION=1.16.5
+ARG GO_VERSION=1.16.6
 ARG DEBIAN_FRONTEND=noninteractive
 ARG VPNKIT_VERSION=0.5.0
 ARG DOCKER_BUILDTAGS="apparmor seccomp"

Dockerfile.e2e

@@ -1,4 +1,4 @@
-ARG GO_VERSION=1.16.5
+ARG GO_VERSION=1.16.6
 
 FROM golang:${GO_VERSION}-alpine AS base
 ENV GO111MODULE=off

Dockerfile.simple

@@ -5,7 +5,7 @@
 
 # This represents the bare minimum required to build and test Docker.
 
-ARG GO_VERSION=1.16.5
+ARG GO_VERSION=1.16.6
 
 FROM golang:${GO_VERSION}-buster
 ENV GO111MODULE=off

Dockerfile.windows

@@ -165,7 +165,7 @@ FROM microsoft/windowsservercore
 # Use PowerShell as the default shell
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]
 
-ARG GO_VERSION=1.16.5
+ARG GO_VERSION=1.16.6
 ARG GOTESTSUM_COMMIT=v0.5.3
 
 # Environment variable notes: