Revert "Bump phonopy from 2.26.6 to 2.33.0 (#291)"

This reverts commit 57916f4.

Author: jan-janssen

pyproject.toml

@@ -52,7 +52,7 @@ surface = [
     "pymatgen==2024.11.13",
 ]
 phonopy = [
-    "phonopy==2.33.0",
+    "phonopy==2.26.6",
     "spglib==2.5.0",
 ]
 pyxtal = ["pyxtal==1.0.6"]