Update PR no in changelog entry

Author: jasikpark

v3/UNRELEASED_CHANGELOG.md

@@ -23,7 +23,7 @@ After processing, the content will be moved to the main changelog and this file
 
 ## Fixed
 <!-- Bug fixes -->
-- Added missing window name to request headers, so it can be logged with the window ID by @jasikpark in [#1234](https://github.com/wailsapp/wails/pull/1234)
+- Added missing window name to request headers, so it can be logged with the window ID by @jasikpark in [#4687](https://github.com/wailsapp/wails/pull/4687)
 
 ## Deprecated
 <!-- Soon-to-be removed features -->