Update dependency wyrihaximus/async-test-utilities to v8

Author: renovate[bot]

composer.json

@@ -26,7 +26,7 @@
     },
     "require-dev": {
         "react-parallel/pool-tests": "^4@dev",
-        "wyrihaximus/async-test-utilities": "^7.2"
+        "wyrihaximus/async-test-utilities": "^7.2 || ^8.0"
     },
     "autoload": {
         "psr-4": {