feat: Add Symfony 8 compatibility

[Pixelshaped]

Fix #65

Tried to implement it while respecting the intention of the package maintainer @barbieswimcrew

"I’d prefer to move towards supporting named parameters while keeping backward compatibility for now — so a compat layer that still handles the array-based options would make sense."

[Pixelshaped]

I had to modify compatibility by constraining versions of symfony/validator in e642f8c to unbreak CI under Composer’s security blocking (PKSA-w2tw-kmfg-rt9s), but I’m not sure we should merge this as-is.

This might prevent some users that were previously eligible to the package to install it and could be considered a breaking change. Maybe the CI rules should be loosened instead.

But I'd rather discuss it than make the call.

[stof]

This might prevent some users that were previously eligible to the package to install it and could be considered a breaking change.

if Composer does not install the new version because it knows there is an incompatibility, there is no BC break

[Pixelshaped]

if Composer does not install the new version because it knows there is an incompatibility, there is no BC break

Then I guess we're in the clear? Let me know if this needs anything else.

[stof]

LGTM (but I'm not a maintainer of that package)