Add use_scm_version directive to setup.py

As per documentation we are required to specify 'use_scm_version=True'
as an argument to setup.py (2020-01-21).

See https://pypi.org/project/setuptools-scm/3.4.2/ reference.

setup.py

@@ -3,4 +3,4 @@
 import setuptools
 
 if __name__ == "__main__":
-    setuptools.setup()
+    setuptools.setup(use_scm_version=True)