composer(deps): update slevomat/coding-standard requirement

Updates the requirements on [slevomat/coding-standard](https://github.com/slevomat/coding-standard) to permit the latest version.
- [Release notes](https://github.com/slevomat/coding-standard/releases)
- [Commits](slevomat/coding-standard@8.15.0...8.16.0)

---
updated-dependencies:
- dependency-name: slevomat/coding-standard
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

composer.json

@@ -36,7 +36,7 @@
     "ext-tokenizer": "*",
     "dealerdirect/phpcodesniffer-composer-installer": "^1.0.0",
     "friendsofphp/php-cs-fixer": "^3.70.0",
-    "slevomat/coding-standard": "~8.15.0",
+    "slevomat/coding-standard": "~8.16.0",
     "squizlabs/php_codesniffer": "^3.11.3"
   },
   "require-dev": {