Use setuptools<81 to access pkg_resources.

Author: moorepants

multibody-book-env.yml

@@ -13,7 +13,7 @@ dependencies:
   - pythreejs ==2.4.2
   - scikits.odes ==3.1.1
   - scipy ==1.16.0
-  - setuptools
+  - setuptools <81  # for pkg_resources
   - sympy ==1.14.0
   # development (can be latest versions)
   - ghp-import