Add pyproject.toml.

Also updated cuda requires to include cupy.

Author: prabhuramachandran

pyproject.toml

@@ -0,0 +1,9 @@
+[build-system]
+requires = [
+    "wheel",
+    "setuptools",
+    "oldest-supported-numpy",
+    "Cython>=0.20",
+    "mako",
+    "pytools"
+]

setup.py

@@ -24,7 +24,7 @@ def get_version():
 if sys.version_info[0] < 3:
     tests_require += ['mock>=1.0']
 docs_require = ['sphinx']
-cuda_require = ['pycuda']
+cuda_require = ['pycuda', 'cupy']
 opencl_require = ['pyopencl']
 
 classes = '''