CONTRIBUTING: Fix link to Node packages.

[joshgav]

No description provided.

[msftclas]

Hi @joshgav, I'm your friendly neighborhood Microsoft Pull Request Bot (You can call me MSBOT). Thanks for your contribution!

It looks like you're a Microsoft contributor (Josh Gavant). If you're full-time, we DON'T require a Contribution License Agreement. If you are a vendor, please DO sign the electronic Contribution License Agreement. It will take 2 minutes and there's no faxing! https://cla.microsoft.com.

TTYL, MSBOT;

[jeffyoung]

Thanks for your contribution Josh (and for pointing to the updated docs)!