Update default tag to stable API version (Azure#24392)

Author: rheajain

specification/paloaltonetworks/resource-manager/readme.md

@@ -27,7 +27,7 @@ These are the global settings for the PaloAltoNetworks.Cloudngfw.
 ```yaml
 openapi-type: arm
 openapi-subtype: rpaas
-tag: package-2022-08-29-preview
+tag: package-2022-08-29
 ```
 
 ### Tag: package-2022-08-29