chore: Update C# namespace

Google APIs · copybara-github · commit dd1d2325b189 · 2021-01-06T11:05:29.000-08:00
This is a breaking change, but *only* for C#. Google has not yet published a package for this API, so it would only break users who have generated the code themselves.

PiperOrigin-RevId: 350388717
diff --git a/google/devtools/cloudbuild/v1/cloudbuild.proto b/google/devtools/cloudbuild/v1/cloudbuild.proto
@@ -26,6 +26,7 @@ import "google/protobuf/empty.proto";
 import "google/protobuf/field_mask.proto";
 import "google/protobuf/timestamp.proto";
 
+option csharp_namespace = "Google.Cloud.CloudBuild.V1";
 option go_package = "google.golang.org/genproto/googleapis/devtools/cloudbuild/v1;cloudbuild";
 option java_multiple_files = true;
 option java_package = "com.google.cloudbuild.v1";
