Update Classifier

Author: donadigo

setup.py

@@ -17,7 +17,7 @@
     'Development Status :: 4 - Beta',
     'Intended Audience :: Developers',
     'Topic :: Software Development :: Build Tools',
-    'License :: OSI Approved :: GPL3 License',
+    'License :: OSI Approved :: GNU General Public License v3 (GPLv3)',
     'Programming Language :: Python :: 3',
     'Programming Language :: Python :: 3.4',
     'Programming Language :: Python :: 3.5',