Add support for golangci-lint

[nitwof]

https://github.com/golangci/golangci-lint
golang-ci lint is popular linter for golang projects.
It would be nice to have it in overcommit.

I think it can be added on two stages:

• pre-commit - to run only on changed go packages
• pre-push- to run on the whole project

[sds]

Implemented in #680. Thanks!