chore: drop Python 2.6

Author: josegonzalez

Diff for: setup.py

@@ -37,7 +37,6 @@ def open_file(fname):
         'Development Status :: 5 - Production/Stable',
         'Topic :: System :: Archiving :: Backup',
         'License :: OSI Approved :: MIT License',
-        'Programming Language :: Python :: 2.6',
         'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',