Simplify .laminas-ci.json

[boesing]

Feature Request

Q	A
New Feature	yes
RFC	yes
BC Break	yes

Summary

The .laminas-ci.json allows to pass checks which overrides the additional_checks and thus are mutually exclusive. This makes the JSON schema more bloated as we have to provide two configuration combinations with either checks or additional_checks.

The .checks[].job element has is allowed to be a string which also makes it more error-prone.
It also states that it is possible to select an additional "action" which can be used with the CI matrix which is actually not really true as if someone choses another "action", that action also have to parse the job JSON-string and from this perspective, I dont really see the benefit of having checks.

Due to the fact that .checks[].job is a string, it also cannot be validated by the JSON schema which is feature-requested in #49.

Is there any project around which uses the .checks functionality from .laminas-ci.json? If not, I would prefer getting rid of that to simplify the matrix action.

[boesing]

Will get easier with #83 #95 in case we implement JSON schema generation from typescript interfaces.