setup.py: add setuptools_scm to setup_requires
setup.py: add setuptools_scm to setup_requires

required in order to make 'use_scm_version' parameter work

Signed-off-by: Enrico Joerns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

rauc/rauc-hawkbit