add regression test for callable use_scm_version
add regression test for callable use_scm_version

Signed-off-by: Esben Haabendal <da90c138e4a9573086862393cde34fa33d74f6e5@haabendal.dk>

esben/setuptools_scm,RonnyPfannschmidt/setuptools_scm,RonnyPfannschmidt/setuptools_scm,pypa/setuptools_scm,pypa/setuptools_scm