Update dependency phpdocumentor/reflection-docblock to v6

Author: renovate[bot]

composer.json

@@ -23,7 +23,7 @@
     "php": ">=7.0.0",
     "ext-json": "*",
     "symfony/polyfill-mbstring": "~1.0",
-    "phpdocumentor/reflection-docblock": "~4.3 || ~5.0"
+    "phpdocumentor/reflection-docblock": "~6.0"
   },
   "require-dev": {
     "phpunit/phpunit": "~6.0 || ~7.0 || ~9.0"