Please Add Datasource for The Buf Schema Registry

[isso-719]

Tell us more.

I am developing with gRPC.
I want Renovate to automatically update the Protobuf Module that exists in The Buf Schema Registry.

For example, to get the version of grpc-ecosystem/gateway, I have to send the following request.

curl "https://buf.build/buf.alpha.registry.v1alpha1.ResourceService/GetResourceByName" \
-H "Content-Type: application/json" \
-d '{
  "owner": "grpc-ecosystem",
  "name": "gateway"
}'

However, Custom Datasource cannot include request bodies.
Thus, I would like to see a Datasource for The Buf Schema Registry implemented.