Add Symfony 8 and Behat 4 support

[shahinataei-ts]

Summary

This PR adds support for Symfony 8 and Behat 4.

The extension code already has the required return types on process() methods, making it compatible with both Behat 3.x and 4.x interfaces (as noted by @mpdude in #218).

Changes

• Update behat/behat constraint to ^3.22 || ^4.0
• Update symfony/* dependencies to include ^8.0
• Add CI matrix entry for Symfony 8.0 with Behat 4.x-dev

Notes

• Symfony 8 requires Behat 4.x-dev as Behat 3.x doesn't declare Symfony 8 compatibility
• This PR builds on the discussion in Add Symfony 8 support #218, incorporating @mpdude's insight that the extension is already code-compatible

Related

• [4.x] feat: Add Symfony 8 support Behat/Behat#1687 (Symfony 8 support merged into Behat 4.x)
• Add Symfony 8 support #218 (Previous Symfony 8 support PR, still in draft)

[mpdude]

Careful: There is no Behat 4 (yet), so you cannot truly know what the API might look like or how it might change. So maybe it's too early to declare compatibility.

[shahinataei-ts]

Careful: There is no Behat 4 (yet), so you cannot truly know what the API might look like or how it might change. So maybe it's too early to declare compatibility.

Thanks @mpdude, fair point.

You're right that Behat 4 isn't released yet. However, we're blocked on Symfony 8 since Behat 3.x doesn't support it, and the extension only uses core Behat interfaces that are unlikely to change before release.

If you prefer a more conservative approach, I'm happy to:

• Keep ^3.22 only and just add CI testing for 4.x-dev
• Or use ^3.22 || 4.0.x-dev to be explicit about the dev constraint

What works best for this project?