NPM User config path error

[ceuk]

Hey,

see: https://github.com/gsoft-inc/azure-devops-npm-auth/blob/9c2fca43982c3063113154a13cb9a6e4f289b06c/npm-config/index.ts#L13-L15

It's fairly common (I think) to not prefix nested dotfiles with a dot

e.g. mine is at ~/.config/npm/npmrc which causes this script to break as it tries to find the config file at ~/.config/npm/npmrc/.npmrc

Was just going to submit a PR but it might need a bit of thinking about so I'm raising a bug for now