Symfony 8 support

[simonrjones]

Update project to support Symfony 8.0

• Update Composer to support Symfony 8.0
• Add Symfony 8 to test suite in php.yml workflow
• Ensure tests pass on Symfony 8
• Ensure tests pass on PHP 8.4
• Ensure tests pass on PHP 8.5

[vivienlacourba]

@simonrjones I believe this was addressed by:

• Symfony 8 support #12
• Symfony 8 support symfony-frontend#10
• feat: Symfony 8 support frontend#105

[simonrjones]

yes it was - thanks