[ReleasePR storagecache] [Hub Generated] Review request for Microsoft.StorageCache to add version stable/2021-05-01 (#1812)

Create to sync Azure/azure-rest-api-specs#14545
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/master...AzureSDKAutomation:sdkAuto/storagecache?expand=1)

Author: msftbot[bot]