refator: add note about branch develop

Author: PauloASilva

README.md

@@ -1,7 +1,8 @@
 :warning: **OWASP API Security Top 10 2019 RC is waiting for comments and
 contributions.** :warning:
 
-Please check the [PDF][2], [source][3] and [how to contribute][4].
+Please check the [PDF][2] and [how to contribute][4]. The working draft is in
+branch [develop][3].
 
 ---
 
@@ -56,5 +57,5 @@ one.
 [0]: https://www.owasp.org/index.php/User:ErezYalon
 [1]: http://creativecommons.org/licenses/by-sa/3.0/
 [2]: https://github.com/OWASP/API-Security/blob/develop/2019/en/dist/owasp-api-security-top-10.pdf
-[3]: https://github.com/OWASP/API-Security/tree/develop/2019/en/src
+[3]: https://github.com/OWASP/API-Security/tree/develop/
 [4]: https://github.com/OWASP/API-Security/blob/master/CONTRIBUTING.md