Mermade openapi3-examples changed structure

[marcelthole]

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 Adjust relative references also for directly inlined documents #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

[cebe]

Seems structure changed to differentiate between openapi version 3.0 and 3.1. So we can adjust reference when support for 3.1 is implemented.