Compatability with php 8.4

Deprecate implicitly nullable parameter types
https://wiki.php.net/rfc/deprecate-implicitly-nullable-types

Author: srjlewis

lib/Phpfastcache/Cluster/AggregatorInterface.php

@@ -86,7 +86,7 @@ public function getCluster(int $strategy): ClusterPoolInterface;
      *
      * @return void
      */
-    public function aggregateDriverByName(string $driverName, ConfigurationOption $driverConfig = null): void;
+    public function aggregateDriverByName(string $driverName, ?ConfigurationOption $driverConfig = null): void;
 
     /**
      * @param AggregatablePoolInterface $driverPool

lib/Phpfastcache/Cluster/ClusterAggregator.php

@@ -94,7 +94,7 @@ public function aggregateDriver(AggregatablePoolInterface $driverPool): void
      * @throws PhpfastcacheDriverNotFoundException
      * @throws PhpfastcacheLogicException
      */
-    public function aggregateDriverByName(string $driverName, ConfigurationOption $driverConfig = null): void
+    public function aggregateDriverByName(string $driverName, ?ConfigurationOption $driverConfig = null): void
     {
         if (isset($this->cluster)) {
             throw new PhpfastcacheLogicException('The cluster has been already build, cannot aggregate more pools.');

lib/Phpfastcache/Drivers/Redis/Config.php

@@ -98,7 +98,7 @@ public function getDatabase(): ?int
      * @return static
      * @throws PhpfastcacheLogicException
      */
-    public function setDatabase(int $database = null): static
+    public function setDatabase(?int $database = null): static
     {
         return $this->setProperty('database', $database);
     }

lib/Phpfastcache/Exceptions/PhpfastcacheIOException.php

@@ -24,7 +24,7 @@ class PhpfastcacheIOException extends PhpfastcacheCoreException
     /**
      * @inheritdoc
      */
-    public function __construct(string $message = "", int $code = 0, \Throwable $previous = null)
+    public function __construct(string $message = "", int $code = 0, ?\Throwable $previous = null)
     {
         $lastError = error_get_last();
         if ($lastError) {

lib/Phpfastcache/Helper/Psr16Adapter.php

@@ -49,7 +49,7 @@ class Psr16Adapter implements CacheInterface
      * @throws PhpfastcacheDriverException
      * @throws PhpfastcacheDriverNotFoundException
      */
-    public function __construct(string|ExtendedCacheItemPoolInterface $driver, ConfigurationOptionInterface $config = null)
+    public function __construct(string|ExtendedCacheItemPoolInterface $driver, ?ConfigurationOptionInterface $config = null)
     {
         if ($driver instanceof ExtendedCacheItemPoolInterface) {
             if ($config !== null) {