Fix a py2 compatibility issue in setup.py

Encoding is not a valid arg for open() in earlier versions of
python.

Author: TkTech

setup.py

@@ -2,8 +2,8 @@
 
 from os import path
 this_directory = path.abspath(path.dirname(__file__))
-with open(path.join(this_directory, 'README.md'), encoding='utf-8') as f:
-    long_description = f.read()
+with open(path.join(this_directory, 'README.md'), 'rb') as f:
+    long_description = f.read().decode('utf-8')
 
 
 setup(