try suggested change

Author: eduardlleshi

.github/workflows/run-tests.yml

@@ -9,7 +9,7 @@ jobs:
             fail-fast: true
             matrix:
                 os: [ubuntu-latest]
-                php: [8.0, 7.4, 7.3]
+                php: [8.1, 8.0, 7.4, 7.3]
                 dependency-version: [prefer-lowest, prefer-stable]
 
         name: P${{ matrix.php }} - ${{ matrix.dependency-version }}

composer.json

@@ -8,7 +8,7 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^9.3.9",
-        "orchestra/testbench": "^6.0.0|^7.0.0"
+        "orchestra/testbench": "^6.23.0|^7.0.0"
     },
     "license": "MIT",
     "authors": [