create-meta/ruby: Create messages rather than plain hashes

[aurelien-reeves]

Summary

The ruby implementation of create-meta did not create proper messages but plain ruby hashes. That is responsible for generating ndjson with snake_case key for protocol_version.

Details

I have converted the meta hashes into messages DTOs

Motivation and Context

While working on reactivating the CCK for cucumber-ruby, it appears that meta.protocol_version was not camelized in the resulting ndjson

How Has This Been Tested?

I have used the existing spec, and added one to make sure the CI was also properly filled

Types of changes

• Bug fix (non-breaking change which fixes an issue).

Checklist:

• The change has been ported to Ruby.
• I've added tests for my code.
• I have updated the CHANGELOG accordingly.