Add note to UPGRADING.INTERNALS about Attribute API changes

Signed-off-by: Bob Weinand <[email protected]>

Author: bwoebi

UPGRADING.INTERNALS

@@ -32,6 +32,9 @@ PHP 8.2 INTERNALS UPGRADE NOTES
 * Deprecated zend_atoi() and zend_atol(). Use ZEND_STRTOL() for general purpose
   string to long conversion, or a variant of zend_ini_parse_quantity() for
   parsing ini quantities.
+* zend_internal_attribute_register() no longer takes a flags argument nor
+  registers the attribute class directly. Instead specify #[Attribute] with the
+  appropriate target flags in the .stub.php file.
 
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