MNT: Use codecs.open for README.md.

Author: hhslepicka

setup.py

@@ -1,5 +1,6 @@
 from setuptools import setup, find_namespace_packages
 from os import path
+from codecs import open
 import versioneer
 
 cur_dir = path.abspath(path.dirname(__file__))
@@ -13,7 +14,7 @@
     cmdclass=versioneer.get_cmdclass(),
     packages=find_namespace_packages(include=['botcity.*']),
     url='https://www.github.com/botcity-dev/botcity-framework-web-python',
-    long_description=open('README.md').read(),
+    long_description=open('README.md', 'r', encoding='utf-8').read(),
     long_description_content_type='text/markdown',
     install_requires=requirements,
     include_package_data=True,