[prgTW]

Problem

• Symfony dependencies are capped at ^4.0, and symfony/security has no 5.x release, so the bundle cannot be installed next to Symfony 5.
• The bundle loads YAML config but does not require symfony/yaml.
• No tests or CI.

Solution

• Require symfony/security-core instead of symfony/security (the voter only uses security-core interfaces).
• Symfony constraints become ^2.8 || ^3.0 || ^4.0 || ^5.4 || ^6.4; symfony/yaml is required with the same range. No PHP code changes.
• A container-build test and a GitHub Actions matrix (lowest deps, Symfony 3.4, 4.4, 5.4, 6.4).

Verification

The matrix passes locally and in CI. Ranges only widen, so this can be released as v3.1.0.