Revert "Add 'Programming Language :: Julia'" (#470)

Got:

> Invalid value for classifiers. Error: Classifier 'Programming Language :: Julia' is not a valid classifier.

https://github.com/JuliaPy/pyjulia/runs/3993407189?check_suite_focus=true#step:7:22

Author: tkf

setup.py

@@ -69,7 +69,6 @@ def pyload(path):
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
-        'Programming Language :: Julia',
       ],
       url='http://julialang.org',
       project_urls={