Update Dumper.php

[devman1917]

now after generate array generated like this

servers:
  -
    url: 'http://support_front'
  -
    url: 'http://support_front'

but most be like this

servers:
  - url: 'http://support_front'
  - url: 'http://support_front'

that's work but not canonical and i fixed

[github-actions]

Thanks for your Pull Request! We love contributions.

However, you should instead open your PR on the main repository:
https://github.com/symfony/symfony

This repository is what we call a "subtree split": a read-only subset of that main repository.
We're looking forward to your PR there!