ci: Renovate ignores Grpc.Core Closes #7148
ci: Renovate ignores Grpc.Core
Closes #7148

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