Go builds fail in build_static.sh

[viscountstyx]

Currently go builds fail inside the alpine container for two reasons:

1.) The alpine 3.8 ca-certificates package does not have an up-to-date Let's Encrypt Root certificate - meaning SSL verification fails for getting the gopkg.in/alecthomas/kingpin.v2 go package. Updating to Alpine 3.14 resolves this as it has a more up to date certificate.

2.) Builds fail with newer versions of golang, where export GO111MODULE=auto is not set as an environment variable in the build script

I've created pull request #18 to resolve both of these. Please review and merge if appropriate :)