Relax Numpy and Python requirements.

$OpenBSD: patch-setup_py,v 1.1 2020/12/09 09:52:23 martin Exp $

Index: setup.py
--- setup.py.orig
+++ setup.py
@@ -29,8 +29,7 @@ NUMPY_MIN_VERSIONS = [
     # Numpy    Python
     ('1.12',   "=='3.6'"),
     ('1.14.5', "=='3.7'"),
-    ('1.17.5', "=='3.8'"),
-    ('1.19.3', ">='3.9'"),
+    ('1.16.5', ">='3.8'"),
 ]
 
 # these are required to use h5py
