chore(1.x): enable testing on PHP 8.3 (#3933)

.github/workflows/REUSABLE_backend.yml

@@ -25,7 +25,7 @@ on:
         description: Versions of PHP to test with. Should be array of strings encoded as JSON array
         type: string
         required: false
-        default: '["7.3", "7.4", "8.0", "8.1", "8.2"]'
+        default: '["7.3", "7.4", "8.0", "8.1", "8.2", "8.3"]'
 
       php_extensions:
         description: PHP extensions to install.
@@ -91,6 +91,8 @@ jobs:
           # Include testing PHP 8.2 with deprecation warnings disabled.
           - php: 8.2
             php_ini_values: error_reporting=E_ALL & ~E_DEPRECATED & ~E_USER_DEPRECATED
+          - php: 8.3
+            php_ini_values: error_reporting=E_ALL & ~E_DEPRECATED & ~E_USER_DEPRECATED
 
         # To reduce number of actions, we exclude some PHP versions from running with some DB versions.
         exclude: