update quickstart region tag
update quickstart region tag

jsimonweb/csharp-docs-samples,jsimonweb/csharp-docs-samples,jsimonweb/csharp-docs-samples,GoogleCloudPlatform/dotnet-docs-samples,GoogleCloudPlatform/dotnet-docs-samples,GoogleCloudPlatform/dotnet-docs-samples,jsimonweb/csharp-docs-samples,GoogleCloudPlatform/dotnet-docs-samples