Update dependency phpstan/phpstan to ^2.1.18 (#54)

* Update dependency phpstan/phpstan to ^2.1.18

| datasource | package         | from   | to     |
| ---------- | --------------- | ------ | ------ |
| packagist  | phpstan/phpstan | 2.1.17 | 2.1.18 |

* SA fix

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Filippo Tessarotto <[email protected]>

Author: renovate[bot]

composer.json

@@ -14,7 +14,7 @@
         "php": "~8.3.0 || ~8.4.0"
     },
     "require-dev": {
-        "phpstan/phpstan": "^2.1.17",
+        "phpstan/phpstan": "^2.1.18",
         "phpstan/phpstan-phpunit": "^2.0.6",
         "phpstan/phpstan-strict-rules": "^2.0.4",
         "phpunit/phpunit": "^12.2.7",

tests/ErrorHandlerTest.php

@@ -113,7 +113,7 @@ public function testHandleCliException(): void
         $this->errorHandler->exceptionHandler($this->exception);
 
         \fseek($memoryStream, 0);
-        $output = (string) \stream_get_contents($memoryStream);
+        $output = \stream_get_contents($memoryStream);
         self::assertStringContainsString($this->exception->getMessage(), $output);
     }