change api version in readme for sdk release (Azure#16187)

* Add blockchain to latest profile

* Add additional types

* api version change

Co-authored-by: Mark Cowlishaw <markcowl@microsoft.com>
Co-authored-by: Ping Zhu <pizh@Pings-MacBook-Pro.local>

specification/fluidrelay/resource-manager/readme.md

@@ -28,7 +28,7 @@ These are the global settings for the adp.
 title: FluidRelayManagementClient
 openapi-type: arm
 openapi-subtype: rpaas
-tag: package-2021-03-12-preview
+tag: package-2021-06-15-preview
 ```
 
 ### Tag: package-2021-03-12-preview