Add Python 3.8 to setup.py

Author: tleonhardt

setup.py

@@ -27,6 +27,7 @@
 Programming Language :: Python :: 3.5
 Programming Language :: Python :: 3.6
 Programming Language :: Python :: 3.7
+Programming Language :: Python :: 3.8
 Programming Language :: Python :: Implementation :: CPython
 Topic :: Software Development :: Libraries :: Python Modules
 """.splitlines())))