Update readme.python.md (Azure#22545)

* Update readme.python.md

* Update readme.python.md

* Update readme.python.md

---------

Co-authored-by: Yuchao Yan <[email protected]>

Author: 2 people

specification/databox/resource-manager/readme.python.md

@@ -22,6 +22,7 @@ Generate all API versions currently shipped for this package
 
 ```yaml $(python)
 multiapi: true
+default-api-version: "2022-12-01"
 batch:
   - tag: package-2022-12
   - tag: package-2022-10