Remove numpy Python version restriction

This was originally added when numpy didn't support Python 3.12, but
that has long since been resolved.

Author: swt2c

requirements/install.txt

@@ -1,4 +1,4 @@
 # Runtime dependencies needed when using wxPython Phoenix
-numpy ; python_version >= '3.0' and python_version < '3.12'
+numpy
 # pillow < 3.0
 typing-extensions; python_version < '3.11'