MAINT: Pin numpy at version 1.x

Author: oesteban

setup.cfg

@@ -23,7 +23,7 @@ url = https://github.com/nipy/nitransforms
 [options]
 python_requires = >= 3.8
 install_requires =
-    numpy >= 1.21.0
+    numpy ~= 1.21
     scipy >= 1.6.0
     nibabel >= 3.0
     h5py