ENH: only create requires.txt when requires is not empty for compatibility with setuptools.
ENH: only create requires.txt when requires is not empty for compatibility with setuptools.

cournape/Bento,abadger/Bento,abadger/Bento,abadger/Bento,cournape/Bento,cournape/Bento,abadger/Bento,cournape/Bento