Fix import order in setup.py

The sys module should be imported first to decalre msspec
path as soon as possible. It enables to load the version module
necessary to avoid hardcoded version number in the setup.py file.
Please note that this import order is not pep8 compliant.

src/setup.py

@@ -21,10 +21,10 @@
 # Last modified: mar. 07 avril 2020 17:01:42
 # Committed by : "Sylvain Tricot <sylvain.tricot@univ-rennes1.fr>"
 
-from setuptools import setup, find_packages
-from version import __version__
 import sys
 sys.path.insert(0, "msspec")
+from setuptools import setup, find_packages
+from version import __version__
 
 
 with open('setup_requirements.txt', 'r') as fd: