update PyDolphinScheduler documentation link. (#11474)

(cherry picked from commit c59a8503)

dolphinscheduler-python/pydolphinscheduler/setup.py

@@ -139,7 +139,7 @@ setup(
     ],
     project_urls={
         "Homepage": "https://dolphinscheduler.apache.org",
-        "Documentation": "https://dolphinscheduler.apache.org/python/index.html",
+        "Documentation": "https://dolphinscheduler.apache.org/python/dev/index.html",
         "Source": "https://github.com/apache/dolphinscheduler/tree/dev/dolphinscheduler-python/"
         "pydolphinscheduler",
         "Issue Tracker": "https://github.com/apache/dolphinscheduler/issues?"