keep benchmark python version consistent

benchmarks/bm_runner.py

@@ -62,7 +62,7 @@ def _check_requirements(package: str) -> None:
 
 def _prep_data_gen_env() -> None:
     """Create or access a separate, unchanging environment for generating test data."""
-    python_version = "3.12"
+    python_version = "3.10"
     data_gen_var = "DATA_GEN_PYTHON"
     if data_gen_var in environ:
         echo("Using existing data generation environment.")