Updated to version 0.4.2. Use promise package

Author: syrusakbary

setup.py

@@ -24,7 +24,7 @@ def run_tests(self):
 
 setup(
     name='graphql-relay',
-    version='0.4.1',
+    version='0.4.2',
 
     description='Relay implementation for Python',
     long_description=open('README.rst').read(),
@@ -55,7 +55,7 @@ def run_tests(self):
 
     install_requires=[
         'graphql-core>=0.5.0',
-        'pypromise>=0.4.0'
+        'promise>=0.4.0'
     ],
     tests_require=['pytest>=2.7.2'],
     extras_require={