Guide to "Upgrading a Third-Party Bundle for a Major Symfony Version" is outdated

[GromNaN]

URL: https://symfony.com/doc/7.4/setup/bundles.html
Source: https://github.com/symfony/symfony-docs/blob/5fdca73c8b3cd747559373ceff6938942e84a8e3/setup/bundles.rst

• The target version should be 8.0 instead of 3.0, to avoid appearing to be reading outdated documentation
• Travis CI configuration should be replaced by GitHub Actions
• A link to https://github.com/GromNaN/symfony-config-xml-to-php can be added