Update dependency symfony/yaml to v8

| datasource | package      | from   | to    |
| ---------- | ------------ | ------ | ----- |
| packagist  | symfony/yaml | 7.4.15 | 8.1.2 |

Author: renovate[bot]

composer.json

@@ -20,7 +20,7 @@
         "michelf/php-markdown": "^2.0",
         "monolog/monolog": "^3.9.0",
         "psr/log": "^3.0.2",
-        "symfony/yaml": "^7.4.1",
+        "symfony/yaml": "^8.1.2",
         "twig/twig": "^3.22.1"
     },
     "require-dev": {