Add feature for creating mirrors of Golang-based tools

[trallnag]

Already requested once, but OP closed issue #164.

Why does it make sense to add support for Go even though pre-commit itself already supports Go? Some projects don't want to add a pre-commit hook to their respective repository. For example mvdan/gofumpt (see this issue). Getting this feature in pre-commit-mirror-maker would make it easier to maintain a mirror.