Fixed classifier spacing

Author: anselor

plugins/ext_test/setup.py

@@ -48,8 +48,8 @@
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
-        'Programming Language:: Python:: 3.8',
-        'Programming Language:: Python:: 3.9',
+        'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
     ],
 
     # dependencies for development and testing