setup.py: Drop deprecated license classifiers (#264)

Closes: #263

Author: APN-Pucky

setup.py

@@ -30,7 +30,6 @@
       classifiers=[
           'Development Status :: 5 - Production/Stable',
           'Intended Audience :: Science/Research',
-          'License :: OSI Approved :: MIT License',
           'Programming Language :: Python :: 3',
           'Programming Language :: Python :: 3.9',
           'Programming Language :: Python :: 3.10',