[V3] Remove npm dependency

[bastienmoulia]

Linked to #350

[yvele]

Yep, having a local dependency to npm-check-updates makes having his npm v3 in nodes_modules/.bin, and makes npm scripts using it instead of the global npm.

Resulting in lot of bugs (exactly like parshap/check-node-version#12)

[vdh]

It looks like npmi will also need to be removed? Otherwise its dependency to npm will still install the second copy.

[raineorshine]

Yes, npmi needs to be removed as well.

[maxleiko]

You guys can bump npmi to 4.0.0 in order to get rid of the npm 👍

[raineorshine]

Closing as the local npm has been removed in the soon-to-be-released v3.