2.x psr log and php multi compat

[luislard]

This pull request fixes issue #.

What's Included in This Pull Request

• Add support for psr/log 2 and 3
• Copied TestLogger class since it is not possible to support importing it for php7 and php8 in the same composer.json
• Enhancements in the Giihub workflows.
• Removed coverage since it was hardcoded to PHP 7.4.

Aditional information

Supporting 3 versions of psr/log is making composer incapable to resolve to version 2 in the tests.

I ran PHPUnit tests in my local using nektos/act modifying composer.json to see the results and it passes.

act --workflows .github/workflows/php-unit-tests.yml push

The min version required of monolog has to be 2.0.1 because the BufferHandler does not meet the interface FormattableHandlerInterface see:

https://github.com/Seldaek/monolog/commit/f9d56fd2f5533322caccdfcddbb56aedd622ef1c

Let me know your thoughts.