[FIX] debug python 3.9 (#132)

* debug python 3.9

* Revert "debug python 3.9"

This reverts commit 7015168.

* change version of scipy, depending on stan

Author: jdkent

setup.cfg

@@ -27,7 +27,8 @@ install_requires =
     numpy>=1.8.0,<2.0; python_version == "3.9" and extra == 'stan'
     numpy>=1.8.0; python_version != "3.9" or extra != 'stan'
     pandas
-    scipy
+    scipy<1.13; python_version == "3.9" and extra == 'stan'
+    scipy; python_version != "3.9" or extra != 'stan'
     sympy
     wrapt
 packages = find: