Use https for Help URLs

README.md

@@ -70,9 +70,9 @@ Here’s how we suggest you go about proposing a change to this project:
 Using the web-based interface to make changes is fine too, and will help you
 by automatically forking the project and prompting to send a pull request too.
 
-[fork]: http://help.github.com/forking/
+[fork]: https://help.github.com/forking/
 [branch]: https://help.github.com/articles/creating-and-deleting-branches-within-your-repository
-[pr]: http://help.github.com/pull-requests/
+[pr]: https://help.github.com/pull-requests/
 
 ## License