fix license classifier in setup.py

Author: zer1t0

setup.py

@@ -18,7 +18,7 @@
     packages=setuptools.find_packages(),
     classifiers=[
         "Programming Language :: Python :: 3",
-        "License :: OSI Approved :: GNU AGPLv3 License",
+        "License :: OSI Approved :: GNU Affero General Public License v3 or later (AGPLv3+)",
         "Operating System :: OS Independent",
     ],
     python_requires='>=3.6',