Add docs requirements as data file

Author: smokestacklightnin

setup.py

@@ -237,6 +237,7 @@ def select_constraint(default, nightly=None, git_master=None):
     packages=find_packages(),
     include_package_data=True,
     package_data={"": ["*.lib", "*.pyd", "*.so"]},
+    data_files=[("docs_reqs", ["requirements-docs.txt"])],
     zip_safe=False,
     distclass=_BinaryDistribution,
     description="A library for exploring and validating machine learning data.",