Outdated blurb in the readme about npm version support

[ahutchings]

The readme has this outdated blurb that indicates that npm 3 is not supported -

NOTE: This currently only works with npm@2, due to this issue affecting npm@3.

This package is a fork of shonkwrap, which provides a great experience for npm 3.x users.

Would you accept a pull request to remove it? Do you still want to mention shonkwrap somewhere?

[evocateur]

Apologies for the delay, I would indeed appreciate a pull request!

I'm okay with removing the note and the shonkwrap mention, though perhaps clarifying that we need npm 3.10.10 or greater for full compatibility with the shrinkwrap lifecycle.