caddy 2.1.0 added support for HTTP2 cleartext connections but the syntax is a bit cumbersome:

https://grpc-api.example.com {
    reverse_proxy localhost:8080 {
        transport http {
            versions h2c 2
        }
    }
}

It would be nice if we could use h2c:// instead:

https://grpc-api.example.com {
    reverse_proxy h2c://localhost:8080
}

Traefik is using the same syntax: https://docs.traefik.io/user-guides/grpc/