[Synapse] - Build SDK based on API version 2021-04-01-preview and add SQL DW Gen3 API (2020-04-01-preview) (Azure#21769)

* [Synapse] - Build SDK based on 2021-04-01-preview and add SQL v3 support

* Update session records

* Regenerate code based on the latest swagger

* Minor fix

Co-authored-by: Dongwei Wang <[email protected]>

Author: idear1203

eng/mgmt/mgmtmetadata/synapse_resource-manager.txt

@@ -4,11 +4,11 @@ Commencing code generation
 Generating CSharp code
 Executing AutoRest command
 cmd.exe /c autorest.cmd https://github.com/Azure/azure-rest-api-specs/blob/master/specification/synapse/resource-manager/readme.md --csharp --version=v2 --reflect-api-versions --csharp-sdks-folder=D:\code\AzureSDK\azure-sdk-for-net\sdk
-2021-03-30 07:43:41 UTC
+2021-06-29 09:07:37 UTC
 Azure-rest-api-specs repository information
 GitHub fork: Azure
 Branch:      master
-Commit:      169c6171bad2f782dc1cd5f23bcb803ce7649b0b
+Commit:      467afe850ec9f7dd60c09b34ead7b60388c89d8a
 AutoRest information
 Requested version: v2
 Bootstrapper version:    [email protected]