Make setup.py PEP-517 compliant

Taken from mattloper#58.

Author: jerinphilip

setup.py

@@ -5,18 +5,8 @@
 """
 
 from distutils.core import setup
-try: # for pip >= 10
-    from pip._internal.req import parse_requirements
-except ImportError: # for pip <= 9.0.3
-    from pip.req import parse_requirements
 from runpy import run_path
 
-install_reqs = parse_requirements('requirements.txt', session=False)
-try:  # for pip < 20.1
-    install_requires = [str(ir.req) for ir in install_reqs]
-except AttributeError:  # for pip >= 20.1
-    install_requires = [str(ir.requirement) for ir in install_reqs]
-
 def get_version():
     namespace = run_path('chumpy/version.py')
     return namespace['version']
@@ -29,8 +19,11 @@ def get_version():
     url='https://github.com/mattloper/chumpy',
     description='chumpy',
     license='MIT',
-    install_requires=install_requires,
-
+    install_requires=[
+        'numpy>=1.8.1',
+        'scipy>=0.13.0',
+        'six>=1.11.0',
+        ],
     # See https://pypi.python.org/pypi?%3Aaction=list_classifiers
     classifiers=[
         # How mature is this project? Common values are