allow --node 5 to get latest 5.x release

[algesten]

This is a feature request.

For nvm it's enough to specify node version as 5 which today will be translated to 5.1.1.

Would be nice of the --node option for nar could do the same.

[h2non]

You can use: --node latest to fetch the latest stable version of node.js. I don't have plans to support your proposal, but I'm open to PR. To support what you're looking for, you can simply process this file and resolve the proper version based on semver comparison functions.