Mermade openapi3-examples changed structure

**IS**
- The repository https://github.com/Mermade/openapi3-examples has changes in the directory structure.
- the current composer.json references the `master` branch as 1.0.0 version
- in #107 a fix was applied to use the latest commit with the old structure

*SHOULD**
- The tests works with the new directory structure of Mermade/openapi3-examples

Inspect composer.json and the test setup that uses Mermade/openapi3-examples, then compare the current dependency structure with the repository's expected paths. Review issue #107 for the prior workaround; done means the tests work with the new directory structure and the dependency reference is consistent.

Vom Indexierungsmodell aus dem Issue-Text verfasst.