chore: add CHANGELOG entry

Author: route

CHANGELOG.md

@@ -10,6 +10,7 @@
 - `Ferrum::Network::Exchange#loader_id` returns loader id [#426]
 - `Ferrum::Browser#debug` opens headless session in the browser devtools frontend [#519]
 - `Ferrum::Frame#parent` returns the parent frame if this frame is nested [#523]
+- `Ferrum::Frame#frame_element` returns the element in which the window is embedded [#524]
 
 ### Changed
 

README.md

@@ -1088,6 +1088,10 @@ Parent frame id if this one is nested in another one.
 
 Parent frame if this one is nested in another one.
 
+#### frame_element : `Node | nil`
+
+Returns the element in which the window is embedded.
+
 #### execution_id : `Integer`
 
 Execution context id which is used by JS, each frame has it's own context in