Fix PHP 8.4 compatibility issues

Author: estevao90

arrays.php

@@ -2,7 +2,7 @@
 /**
  * Plugin Name: Arrays
  * Description: Arrays library with a plugin bootstrap file for automated testing.
- * Version: 1.0.0
+ * Version: 1.3.4
  * Author: StellarWP
  * Author URI: https://stellarwp.com
  */

src/Arrays/Arr.php

@@ -345,7 +345,7 @@ public static function filter_prefixed( array $array, string $prefix ): array {
 	 *
 	 * @return mixed
 	 */
-	public static function first( $array, callable $callback = null, $default = null ) {
+	public static function first( $array, callable ?$callback = null, $default = null ) {
 		if ( is_null( $callback ) ) {
 			if ( empty( $array ) ) {
 				return self::value( $default );
@@ -707,7 +707,7 @@ public static function join( $array, $glue, $finalGlue = '' ) {
 	 *
 	 * @return mixed
 	 */
-	public static function last( $array, callable $callback = null, $default = null ) {
+	public static function last( $array, callable ?$callback = null, $default = null ) {
 		if ( is_null( $callback ) ) {
 			return empty( $array ) ? self::value( $default ) : end( $array );
 		}