fix packaging reference to readme file

Author: simon-weber

MANIFEST.in

@@ -1,6 +1,6 @@
 include HISTORY.rst
 include LICENSE
-include README.rst
+include README.md
 include python/boto/endpoints.json
 include aws_lambda/project_template/config.yaml
 recursive-include tests *.json *.py *.txt *.yaml

setup.py

@@ -5,7 +5,7 @@
 from setuptools import find_packages
 from setuptools import setup
 
-with open('README.rst') as readme_file:
+with open('README.md') as readme_file:
     readme = readme_file.read()
 
 requirements = [