Fix missing comma

Author: qubvel

setup.py

@@ -129,7 +129,7 @@ def run(self):
     classifiers=[
         # Trove classifiers
         # Full list: https://pypi.python.org/pypi?%3Aaction=list_classifiers
-        "License :: OSI Approved :: Apache Software License"
+        "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
         "Programming Language :: Python :: Implementation :: CPython",