Upgrade deprecated actions/cache in workflow to v4

Upgraded actions/cache to v4 in accordance with notice of v1/v2 package closing down.

https://github.blog/changelog/2024-12-05-notice-of-upcoming-releases-and-breaking-changes-for-github-actions/#actions-cache-v1-v2-and-actions-toolkit-cache-package-closing-down

Symfony 6 and PHP 8.3 support

Also drop deprecated allowances.

Update phpcs-tool to 9.1.0 with Hostnet-Level-2

• Update phpcs-tool to 9.1.0 with Hostnet-Level-2

Symfony 5 support

Merge pull request #28 from nutama/symfony-5

added support for symfony 5

Resolved incorrect 'hostnet/entity-tracker-component'-version

Resolved incorrect 'hostnet/entity-tracker-component' version (#27)

Version upgrades and deprecation issues

• PHP 7.2 is now the minimum requirement
  • Type hints have been added to all functions
• This bundle is now Symfony 4 only

Allow Symfony 4

Updates composer.json to allow symfony 4.

entity-tracker-component 2.0.0 compat

• use version ^2.0.0 of the entity-tracker-component
• dropped support for php 5.5 since it is EOL
• phpunit 5.5
• test against lowest allowed dependencies in travis

Fix for having symfony/symfony without loading SecurityBundle

BC fix

Remove requirement for symfony/security-bundle

BC fix