Update .asf.yaml

.asf.yaml

 github:
-  description: "A distributed and easy-to-expand visual DAG workflow scheduling system"
+  description: "Dolphin Scheduler is a distributed and easy-to-expand visual DAG workflow scheduling system dedicated to solving the complex dependencies in data processing, making the scheduling system out of the box for data processing"
   homepage: https://dolphinscheduler.apache.org