Migrate CI to GitHub Actions and modernize package for PHP 8.5 / Symfony 7.4

[azine]

Motivation

• Modernize the bundle to target current PHP and Symfony versions and replace legacy CI configuration.
• Simplify developer workflow and ensure tests run on GitHub Actions instead of Travis CI.

Description

• Add .github/workflows/ci.yml to run CI on push and pull requests using PHP 8.5, install dependencies and run composer test.
• Remove legacy .travis.yml and travis.php.ini files and update README.md with new requirements, test instructions, and upgrade notes mentioning GitHub Actions.
• Update composer.json to require php:^8.5, symfony components at ^7.4, bump hybridauth and monolog, switch to psr-4 autoloading, add a test script, and update dev dependencies to phpunit:^12.0 and php-cs-fixer:^3.0 plus minor config keys (sort-packages, allow-plugins).
• Update phpunit.xml.dist to the PHPUnit 12 schema, enable failOnRisky and failOnWarning, set a cache directory, adjust the testsuite and add a <source> include list.

Testing

• No automated test runs were produced as part of this change, but CI is configured to run composer validate and composer test on every push and pull request via the new GitHub Actions workflow.
• Local test commands to run are composer update and composer test as documented in README.md.

---

Codex Task