Upgrade to php 8.1

Use phpunit:10

Author: funivan

composer.json

@@ -18,15 +18,16 @@
         }
     ],
     "require": {
-        "php": ">=8.0",
+        "php": ">=8.1",
         "firebase/php-jwt": "~5.0 || ~6.0",
         "ext-curl": "*"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^3.13",
         "php-coveralls/php-coveralls": "2.5",
-        "phpunit/phpunit": "^9.5",
-        "phpstan/phpstan": "^1.10"
+        "phpunit/phpunit": "^10.0",
+        "phpstan/phpstan": "^1.10",
+        "rector/rector": "^0.19.0"
     },
     "autoload": {
         "psr-0": {

src/Bigcommerce/Api/Connection.php

@@ -609,6 +609,8 @@ public function getHeaders()
      */
     public function __destruct()
     {
-        curl_close($this->curl);
+        if ($this->curl !== null) {
+            curl_close($this->curl);
+        }
     }
 }