codeclimate/codeclimate-rubocop

This cop checks for methods invoked via the :: operator instead
of the . operator (like FileUtils::rmdir instead of FileUtils.rmdir).

### Example:
    # bad
    Timeout::timeout(500) { do_something }
    FileUtils::rmdir(dir)
    Marshal::dump(obj)

    # good
    Timeout.timeout(500) { do_something }
    FileUtils.rmdir(dir)
    Marshal.dump(obj)