fix: ensure the proto/nitric folder is a module

makefile

@@ -30,6 +30,9 @@ grpc-client: install download
 	@echo Generating Proto Sources
 	@echo $(OUTPUT)
 	@mkdir -p $(OUTPUT)
+    # protoc doesn't create the __init__.py for the nitric module, so we need to create it.
+	@mkdir -p $(OUTPUT)/nitric/
+	@touch $(OUTPUT)/nitric/__init.py__
 	@python3 -m grpc_tools.protoc -I $(CONTRACTS) --python_betterproto_out=$(OUTPUT) ./contracts/proto/*/*/*.proto