Bump NumPy's version lower-bound to 1.17.0

Author: Mauko Quiroga

setup.py

@@ -8,7 +8,7 @@
 general_requirements = [
     'dpath >= 1.5.0, < 2.0.0',
     'pytest >= 4.4.1, < 6.0.0',  # For openfisca test
-    'numpy >= 1.11, < 1.21',
+    'numpy >= 1.17.0, < 1.21.0',
     'psutil >= 5.4.7, < 6.0.0',
     'PyYAML >= 3.10',
     'sortedcontainers == 2.2.2',