Use io.open instead of codecs.open

setup.py

@@ -4,7 +4,7 @@
 # Note: To use the 'upload' functionality of this file, you must:
 #   $ pip install twine
 
-import codecs
+import io
 import os
 import sys
 from shutil import rmtree
@@ -31,7 +31,7 @@ here = os.path.abspath(os.path.dirname(__file__))
 
 # Import the README and use it as the long-description.
 # Note: this will only work if 'README.rst' is present in your MANIFEST.in file!
-with codecs.open(os.path.join(here, 'README.rst'), encoding='utf-8') as f:
+with io.open(os.path.join(here, 'README.rst'), encoding='utf-8') as f:
     long_description = '\n' + f.read()
 
 # Load the package's __version__.py module as a dictionary.