chore: Fix handling of regex when selectively building APIs
chore: Fix handling of regex when selectively building APIs

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