refactor: re-add php8.1 and php8.2 checks to pipeline

.gitlab-ci.yml

@@ -13,15 +13,5 @@ phpunit-php8.2:
 
 # Remove the entire phpunit-php8.3 block, to allow PHPUnit to run on PHP 8.3 in your pipeline
 phpunit-php8.3:
-  rules:
-    - when: never
-
-# Disable PHP 8.1 syntax check, as PHP 8.3 is minimum requirement
-php-syntax-check-8.1:
-  rules:
-    - when: never
-
-# Disable PHP 8.2 syntax check, as PHP 8.3 is minimum requirement
-php-syntax-check-8.2:
   rules:
     - when: never
\ No newline at end of file