* Refactor our `utils/fs` locking to use `flock`
library and add support for windows.
Flock works differently on linx/mac vs windows. On windows it's impossible to
read/write file after locking, so we need to create separate lockfile.
- Don't assume an explicit $GOPATH is set
- Remove golint from linters - it's been deprecated for over a year
and golangci-lint prints a warning instead of running it.
Rafał Cieślak