Add php 8.1 support

Author: wojsmol

composer.json

@@ -15,7 +15,7 @@
         "wp-cli/wp-cli": "^2.5"
     },
     "require-dev": {
-        "wp-cli/wp-cli-tests": "^3.0.11"
+        "wp-cli/wp-cli-tests": "^3.1"
     },
     "config": {
         "process-timeout": 7200,