Bug#901253: ITP: golang-github-modern-go-test -- Modern Go test utilities

["Martin Ferrari" <tincho@debian.org>]

Package: wnpp
Severity: wishlist
Owner: Martín Ferrari <tincho@debian.org>

* Package name    : golang-github-modern-go-test
  Version         : 1.0.0-1
  Upstream Author : Modern Go Programming
* URL             : https://github.com/modern-go/test
* License         : Apache-2.0
  Programming Lang: Go
  Description     : Modern Go test utilities

 Make go unit test more readable:
  * C style assert, with clear error message
  * Diff object, if unequal, tells exactly where is the difference
  * JsonEqual to compare complex object graph

Another new transitive dependency for prometheus and json-iterator.