python.pkgs.moto: fix build

add responses to propagatedBuildInputs

pkgs/development/python-modules/moto/default.nix

@@ -1,5 +1,5 @@
 { stdenv, buildPythonPackage, fetchPypi, jinja2, werkzeug, flask
-, requests, pytz, backports_tempfile, cookies, jsondiff, botocore, aws-xray-sdk, docker
+, requests, pytz, backports_tempfile, cookies, jsondiff, botocore, aws-xray-sdk, docker, responses
 , six, boto, httpretty, xmltodict, nose, sure, boto3, freezegun, dateutil, mock, pyaml }:
 
 buildPythonPackage rec {
@@ -40,6 +40,7 @@ buildPythonPackage rec {
     jsondiff
     botocore
     docker
+    responses
   ];
 
   checkInputs = [ boto3 nose sure freezegun ];