Make ServiceServer log calls to unknown methods.

Sources/SwiftGRPC/Runtime/ServiceServer.swift

@@ -84,6 +84,7 @@ open class ServiceServer {
             try handler.sendStatus(responseStatus)
           }
         } catch _ as HandleMethodError {
+          print("ServiceServer call to unknown method '\(unwrappedMethod)'")
           if !handler.completionQueue.hasBeenShutdown {
             // The method is not implemented by the service - send a status saying so.
             try handler.call.perform(OperationGroup(