fix requirements

Author: djsutherland

setup.py

@@ -66,9 +66,8 @@
  license='MIT',
  scripts=[],
  data_files=[],
- requires=["numpy", "scipy", "cython"],
- setup_requires=["numpy>=1.16", "scipy>=1.0", "cython>=0.23"],
- install_requires=["numpy>=1.16", "scipy>=1.0", "cython>=0.23"],
+ setup_requires=["numpy>=1.16", "cython>=0.23"],
+ install_requires=["numpy>=1.16", "scipy>=1.0"],
  classifiers=[
  'Development Status :: 5 - Production/Stable',
  'Intended Audience :: Developers',