.aliases: Update `npm` the right way
.aliases: Update `npm` the right way

`npm install npm -g` is the new recommended way to update npm as specified in the npm-faq at https://github.com/npm/npm/blob/master/doc/misc/npm-faq.md.

Closes #423.

troyxmccall/dotfiles,troyxmccall/dotfiles,troyxmccall/dotfiles