MAINT: Simplify dependencies

Author: mgxd

setup.cfg

@@ -22,10 +22,8 @@ url = https://github.com/nipy/nitransforms
 [options]
 python_requires = >= 3.7
 install_requires =
-    numpy ~= 1.21.0; python_version<'3.8'
-    numpy ~= 1.21; python_version>'3.7'
-    scipy ~= 1.6.0;  python_version<'3.8'
-    scipy ~= 1.6; python_version>'3.7'
+    numpy >= 1.21.0
+    scipy >= 1.6.0
     nibabel >= 3.0
     h5py
 test_requires =