tools: Copy most recent API Index schema
tools: Copy most recent API Index schema

jskeet/google-cloud-dotnet,googleapis/google-cloud-dotnet,jskeet/gcloud-dotnet,googleapis/google-cloud-dotnet,jskeet/google-cloud-dotnet,jskeet/google-cloud-dotnet,jskeet/google-cloud-dotnet,googleapis/google-cloud-dotnet,jskeet/google-cloud-dotnet