UPGRADING: Note Phar::setAlias()/setDefaultStub() return type changes

Follow-up to phpGH-15426 (6836cae)

Author: Ayesh

UPGRADING

@@ -656,6 +656,10 @@ PHP 8.4 UPGRADE NOTES
 - PGSQL:
   . pg_select, the conditions arguments accepts an empty array and is optional.
 
+- Phar:
+  . Phar::setAlias() and Phar::setDefaultStub() methods now have a return type of
+    true instead of bool.
+
 - POSIX:
   . posix_isatty now sets the error number when the file descriptor/stream argument
     is invalid.