Breaking: #15 - Removed TYPO3 v12 and PHP 8.1 support 

Description 

Support for TYPO3 v12 has been removed with version 2.0.0, following the dual TYPO3 core version support per major extension version used as support matrix. Along with it, support for PHP 8.1 has been removed, raising the lowest supported PHP version to PHP 8.2.

This includes the removal of the TYPO3 v12 specific implementations in the FGTCLBEnvironmentStateManagerCore12 namespace, the related functional tests and all build and continuous integration configuration for TYPO3 v12 and PHP 8.1.

Impact 

The extension can not be installed on TYPO3 v12 instances or with PHP 8.1 anymore. Composer refuses the installation of version 2.0.0 in that case.

The classes of the FGTCLBEnvironmentStateManagerCore12 namespace do not exist anymore. Code type-hinting or instantiating them directly fails with a fatal error.

Affected installations 

Instances using TYPO3 v12 or PHP 8.1 together with version 1.x of this extension, and code referencing the FGTCLBEnvironmentStateManagerCore12 classes directly.

Referencing the version specific classes directly has always been discouraged. The documented public API is the version agnostic EnvironmentBuilderFactoryInterface, EnvironmentBuilderInterface, StateManagerInterface and StateInterface, which are unaffected.

Migration 

Upgrade the instance to TYPO3 v13 and PHP 8.2 or higher, either beforehand or within the same step as updating this extension.

Instances which can not be upgraded yet stay on the 1.x releases, maintained in branch 1, which continue to support TYPO3 v12 and v13 with PHP 8.1 and higher.

Replace direct references to Core12 classes with the version agnostic public API interfaces, which resolve to the implementation matching the running TYPO3 core version through dependency injection.