Add 2 more tests and many more typehints

[GenieTim]

Dear @khanamiryan

I want to thank you again for this awesome library and for merging my last PR so fast.

Unfortunately, I had not yet pushed the most important commit, which told composer that the new version is only compatible with PHP 8.1. People noticed (#123, #124, #126) and had some problems.

In this PR, the required line in composer.json is included (as it is also in #125 and #127).
Additionally, I add two more tests and lots of additional typehints, as well as GitHub Actions to run tests and static tests.
The two tests use the image provided in #112, so you could close that one afterwards.

I would suggest that, if you approve my changes, you publish this version as a major one (v2.0.0) and delete version 1.0.6. That would solve the issues people had.

Generally, this PR at least potentially closes #112, #118, #123, #124, #125, #126, #127.

Thanks and best regards,

Tim

[khanamiryan]

Thank you for all improvements and updates you did in this libarary. Unfortunately I don't time to do it myself, but it's great that people use it and doing updates