Update dependency slevomat/coding-standard to ^8.20.0

Author: renovate-runner[bot]

composer.json

@@ -7,7 +7,7 @@
  "php": "^8.2",
  "dealerdirect/phpcodesniffer-composer-installer": "^1.1.2",
  "doctrine/coding-standard": "^13.0.1",
- "slevomat/coding-standard": "^8.19.1",
+ "slevomat/coding-standard": "^8.20.0",
  "squizlabs/php_codesniffer": "^3.13.2"
  },
  "config": {