Updated README.

Author: tallesl

README.md

@@ -39,7 +39,11 @@ Check the [issues]!
 **Want to help?**
 Check the [help wanted] label!
 
+**Looking for the now deprecated version 5 of the library**?
+Check the [version-5] branch!
+
 [master branch]: https://github.com/fluentscheduler/FluentScheduler
 [documentation]: https://fluentscheduler.github.io/v6
 [issues]:        https://github.com/fluentscheduler/FluentScheduler/issues
 [help wanted]:   https://github.com/fluentscheduler/FluentScheduler/labels/help%20wanted
+[version-5]:     https://github.com/fluentscheduler/FluentScheduler/tree/version-5