Fix syntax of classifiers
@@ -40,7 +40,7 @@ setup(
"Topic :: Software Development :: Build Tools",
"Programming Language :: Python",
"Programming Language :: Python :: 3",
- "Programming Language :: Python :: 3 :: Only"
+ "Programming Language :: Python :: 3 :: Only",
"Programming Language :: Python :: 3.6",
"Programming Language :: Python :: 3.7",
"Programming Language :: Python :: 3.8",
