remove sympy support

Author: ferrine

environment.yml

@@ -48,6 +48,5 @@ dependencies:
   - packaging
   - typing_extensions
   # optional
-  - sympy
   - cython
 

pytensor/scalar/basic_sympy.py

@@ -8,7 +8,6 @@ pytest-cov>=2.6.1
 coverage>=5.1
 pytest
 cython
-sympy
 versioneer
 jax
 jaxlib