Optimize diff within CI pipeline output for better readability in case of failing tests

[boesing]

Feature Request

Q	A
New Feature	yes

Summary

In #62, a CI pipeline was created for this action.
Sadly, the output of the integration tests diff are not that easy to understand.

I was thinking of using something like https://github.com/josephburnett/jd

Another "problem" is, that every check has a job property which contains the job as a stringified JSON.
Maybe this might be also fixed with using jd and maybe with a colorized output (not sure if thats even possible for GHA) but if not, using diff to actually do the diff might suffice while using jd to display some kind of "pretty printed JSON".