npm reverted their broken cert
broken link to CONTRIBUTING.md

not saying this line should be removed necessarily, but it is broken. Is there a good `CONTRIBUTING.md` file we could add in here? Maybe from another buildpack?
Merge pull request #113 from dickeyxxx/patch-1

broken link to CONTRIBUTING.md
Merge pull request #107 from heroku/remove-npm-cert-workaround

npm reverted to a backwards compatible cert