require python>3.8 in setup.py

Author: anilbey

setup.py

@@ -21,6 +21,8 @@
 """
 
 import setuptools
+import sys
+
 import versioneer
 
 
@@ -40,6 +42,9 @@
     'arbor>=0.7',
 ]
 
+if sys.version_info < (3, 8):
+    sys.exit("Python version >= 3.8 is required.")
+
 setuptools.setup(
     name="bluepyopt",
     version=versioneer.get_version(),