Update Golang from 1.13 to 1.16 by replacing it with the official tdewolff/minify image
Updates Golang from 1.13 to 1.16, which is used on use of minify, by using the upstream official Docker image.
Also enables us to keep up-to-date in terms of Go version.
https://github.com/tdewolff/minify/blob/master/Dockerfile
https://hub.docker.com/r/tdewolff/minify
Part of &5546 (closed)
Edited by Takuya Noguchi