PHP 8.3 support

Start testing there...

Author: iamcal

.github/workflows/php.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         operating-system: [ubuntu-latest]
-        php-versions: ["5.6", "7.0", "7.1", "7.2", "7.3", "7.4", "8.1", "8.2"]
+        php-versions: ["5.6", "7.0", "7.1", "7.2", "7.3", "7.4", "8.1", "8.2", "8.3"]
         coverage: [false]
 
     steps: