Update PHPUnit tests to be PHP 8.4 compatible

Author: phpfui

tests/Twilio/Holodeck.php

@@ -13,8 +13,8 @@ class Holodeck implements Client {
 
     public function request(string $method, string $url,
                             array $params = [], array $data = [], array $headers = [],
-                            string $user = null, string $password = null,
-                            int $timeout = null): Response {
+                            ?string $user = null, ?string $password = null,
+                            ?int $timeout = null): Response {
         $this->requests[] = new Request($method, $url, $params, $data, $headers, $user, $password);
         if (\count($this->responses) === 0) {
             return new Response(404, null, null);

tests/Twilio/Request.php

@@ -14,7 +14,7 @@ class Request {
 
     public function __construct(string $method, string $url,
                                 ?array $params = [], array $data = [], array $headers = [],
-                                string $user = null, string $password = null) {
+                                ?string $user = null, ?string $password = null) {
         $this->method = $method;
         $this->url = $url;
         $this->params = $params;

tests/Twilio/Unit/ValuesTest.php

@@ -94,7 +94,7 @@ private function testPassingValues(
         int $intVal = Values::INT_NONE,
         bool $boolVal = Values::BOOL_NONE,
         string $stringVal = Values::NONE,
-        \DateTime $dateTimeVal = null
+        ?\DateTime $dateTimeVal = null
     ): array
     {
         $arr = [];