Update process documentation for Kokoro
Update process documentation for Kokoro

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