chore: fix developer doc link in CONTRIBUTING.md (#1546)

Author: andrewseguin

CONTRIBUTING.md

@@ -234,7 +234,7 @@ changes to be accepted, the CLA must be signed. It's a quick process, we promise
 [coc]: https://github.com/angular/code-of-conduct/blob/master/CODE_OF_CONDUCT.md
 [commit-message-format]: https://docs.google.com/document/d/1QrDFcIiPjSLDn3EL15IJygNPiHORgU1_OOAqWjiDU5Y/preview
 [corporate-cla]: http://code.google.com/legal/corporate-cla-v1.0.html
-[dev-doc]: https://github.com/angular/material2/blob/master/DEVELOPER.md
+[dev-doc]: https://github.com/angular/material2/blob/master/DEV_ENVIRONMENT.md
 [github]: https://github.com/angular/material2
 [gitter]: https://gitter.im/angular/material2
 [individual-cla]: http://code.google.com/legal/individual-cla-v1.0.html