Update highest PHP version to 8.3

Author: kenjis

.github/workflows/phpcsfixer.yml

@@ -30,7 +30,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php-versions: ['7.4', '8.2']
+        php-versions: ['7.4', '8.3']
 
     steps:
       - name: Checkout