fix: make sure paths are Paths

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

src/scikit_build_core/builder/builder.py

@@ -232,15 +232,15 @@ def configure(
         numpy_include_dir = get_numpy_include_dir()
 
         # Classic Find Python
-        cache_config["PYTHON_EXECUTABLE"] = sys.executable
+        cache_config["PYTHON_EXECUTABLE"] = Path(sys.executable)
         cache_config["PYTHON_INCLUDE_DIR"] = python_include_dir
         if python_library:
             cache_config["PYTHON_LIBRARY"] = python_library
 
         # Modern Find Python
         for prefix in ("Python", "Python3"):
-            cache_config[f"{prefix}_EXECUTABLE"] = sys.executable
-            cache_config[f"{prefix}_ROOT_DIR"] = sys.prefix
+            cache_config[f"{prefix}_EXECUTABLE"] = Path(sys.executable)
+            cache_config[f"{prefix}_ROOT_DIR"] = Path(sys.prefix)
             cache_config[f"{prefix}_INCLUDE_DIR"] = python_include_dir
             cache_config[f"{prefix}_FIND_REGISTRY"] = "NEVER"
             # FindPython may break if this is set - only useful on Windows