Merge branch '5.3' into 5.4

* 5.3:
  Fix return types for PHP 8.1

Author: derrabus

GenericEvent.php

@@ -118,6 +118,7 @@ public function hasArgument(string $key)
      *
      * @throws \InvalidArgumentException if key does not exist in $this->args
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($key)
     {
         return $this->getArgument($key);
@@ -131,6 +132,7 @@ public function offsetGet($key)
      *
      * @return void
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($key, $value)
     {
         $this->setArgument($key, $value);
@@ -143,6 +145,7 @@ public function offsetSet($key, $value)
      *
      * @return void
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($key)
     {
         if ($this->hasArgument($key)) {
@@ -157,6 +160,7 @@ public function offsetUnset($key)
      *
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function offsetExists($key)
     {
         return $this->hasArgument($key);
@@ -167,6 +171,7 @@ public function offsetExists($key)
      *
      * @return \ArrayIterator
      */
+    #[\ReturnTypeWillChange]
     public function getIterator()
     {
         return new \ArrayIterator($this->arguments);