Update package classifiers (#467)

* Include Python 3.9 and 3.10 classifiers

* Add 'Programming Language :: Julia'

Author: tkf

setup.py

@@ -67,6 +67,9 @@ def pyload(path):
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
+        'Programming Language :: Julia',
       ],
       url='http://julialang.org',
       project_urls={