[ReleasePR appconfiguration] [Azure App Configuration] Add 2021-10-01-preview version (#2184)

Create to sync Azure/azure-rest-api-specs#17444
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/appconfiguration?expand=1)

Author: msftbot[bot]