docs: fix links url in CONTRIBUTING.md

Some urls where kept from angular/devkit and angular/angular-cli before the cli package was moved.

Author: nlm-pro

CONTRIBUTING.md

@@ -239,8 +239,8 @@ 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/edit#
 [corporate-cla]: http://code.google.com/legal/corporate-cla-v1.0.html
-[dev-doc]: https://github.com/angular/angular-cli#development-hints-for-working-on-angular-cli
-[GitHub]: https://github.com/angular/devkit
+[dev-doc]: ttps://github.com/angular/angular-cli/blob/master/packages/angular/cli/README.md#development-hints-for-working-on-angular-cli
+[GitHub]: https://github.com/angular/angular-cli
 [gitter]: https://gitter.im/angular/angular-cli
 [individual-cla]: http://code.google.com/legal/individual-cla-v1.0.html
 [js-style-guide]: https://google.github.io/styleguide/jsguide.html