fix: allow phpunit 9 and enable php coverage driver

Author: joostdebruijn

.github/workflows/tests.yml

@@ -52,7 +52,7 @@ jobs:
         with:
           php-version: ${{ matrix.php }}
           extensions: curl
-          coverage: none
+          coverage: xdebug
 
       - name: Install dependencies
         run: |

composer.json

@@ -20,7 +20,7 @@
     "require-dev": {
         "mockery/mockery": "~1.0",
         "orchestra/testbench": "^7.0|^8.0|^9.0",
-        "phpunit/phpunit": "^10.5"
+        "phpunit/phpunit": "^9.5|^10.5"
     },
     "autoload": {
         "psr-4": {