fix missing requirements.txt in sdist

bump version to 1.0.1 (issue was hard to spot on test pypi due to pyproject.toml not finding setuptools)
add package script

MANIFEST.in

+include requirements.txt
\ No newline at end of file

package.sh

+#!/usr/bin/env bash
+
+ROOT=$(realpath $(dirname $0))
+cd ${ROOT}
+
+python3 -m pip install --upgrade setuptools wheel twine
+python3 setup.py sdist
+echo "Inspect dist and upload with \"python3 -m twine upload dist/*\""

setup.py

@@ -10,7 +10,7 @@ with open('requirements.txt') as f:
 
 setup(
     name='torch_discounted_cumsum',
-    version='1.0.0',
+    version='1.0.1',
     description='Fast discounted cumulative sums in PyTorch',
     install_requires=requirements,
     python_requires='>=3.6',