Add tests for php8.3

Author: frankdekker

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-versions: ['7.4', '8.0', '8.1', '8.2']
+        php-versions: ['7.4', '8.0', '8.1', '8.2', '8.3']
         composer-flags: ['', '--prefer-lowest']
     steps:
       - uses: actions/checkout@v4
@@ -44,7 +44,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 8.0
+          php-version: 8.3
           coverage: none
 
       - name: Install dependencies