Update trove classifiers

Author: lieryan

setup.py

@@ -9,9 +9,12 @@
 
 classifiers = [
     'Development Status :: 6 - Mature',
-    'Programming Language :: Python :: 3.5',
-    'Programming Language :: Python :: 3.6',
+    'Programming Language :: Python',
+    'Programming Language :: Python :: 3',
     'Programming Language :: Python :: 3.7',
+    'Programming Language :: Python :: 3.8',
+    'Programming Language :: Python :: 3.9',
+    'Programming Language :: Python :: 3.10',
     'Operating System :: OS Independent',
     'Environment :: X11 Applications',
     'Environment :: Win32 (MS Windows)',