Raise min version to PHP 8.1, check compatibility PHP 8.4.

[terabytesoftw]

Q	A
Is bugfix?	❌
New feature?	✔️
Breaks BC?	❌

[what-the-diff]

PR Summary

• Update on Workflow File
  The .github/workflows/build.yml file has been revised. Updates include ignoring certain paths for pull request and push events. The environments section has been removed and we've improved the 'phpunit' job by using a custom action from our repository.

• Modification of PHP Requirements
  Our composer.json file now requires PHP version 7.3 as the minimum level. We've updated some dependencies, namely 'phpunit/phpunit' to a newer version 9.6.

• Enhancement in Test Files
  Various methods in the test files (FlattenExceptionTest.php, LogTargetTest.php, ModuleTest.php, PanelTest.php, TestCase.php) have been modified for better performance. Specifically, we've changed certain 'setUp' and 'tearDown' methods and switched assertions 'assertContains' to 'assertStringContainsString'.

• Removal of Unnecessary Inclusion
  We cleaned up bootstrap.php file by removing an unnecessary inclusion of the 'compatibility.php' file.

• File Deletion
  An unneeded file, 'compatibility.php', has been removed from the repository.

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