Update a ReadMe

Author: mdmintz

examples/cdp_mode/ReadMe.md

@@ -420,7 +420,7 @@ sb.cdp.js_dumps(obj_name)
 sb.cdp.maximize()
 sb.cdp.minimize()
 sb.cdp.medimize()
-sb.cdp.set_window_rect()
+sb.cdp.set_window_rect(x, y, width, height)
 sb.cdp.reset_window_size()
 sb.cdp.open_new_window(url=None, switch_to=True)
 sb.cdp.switch_to_window(window)