[py] Make get_screenshot_as_file() work with pathlib.Paths (#11095)

Make `get_screenshot_as_file()` work with pathlib.Paths

Author: NickCrews

py/selenium/webdriver/remote/webdriver.py

@@ -920,7 +920,7 @@ def get_screenshot_as_file(self, filename) -> bool:
 
                 driver.get_screenshot_as_file('/Screenshots/foo.png')
         """
-        if not filename.lower().endswith(".png"):
+        if not str(filename).lower().endswith(".png"):
             warnings.warn(
                 "name used for saved screenshot does not match file " "type. It should end with a `.png` extension",
                 UserWarning,