fix: ruleset deprecated on `v3.18`

[ddevsr]

Closes https://github.com/codeigniter4/CodeIgniter4/issues/7594

Ref:

• https://cs.symfony.com/doc/rules/index.html#namespace-notation
• https://cs.symfony.com/doc/rules/class_notation/final_internal_class.html

[ddevsr]

@paulbalandan Unit test failed on nexus/cs-config?

[paulbalandan]

@paulbalandan Unit test failed on nexus/cs-config?

No. I'll push the fix for ordered_class_elements. Please fix the ordering.

[paulbalandan]

Please rebase.

[ddevsr]

@paulbalandan done

[paulbalandan]

Thank you, @ddevsr