Extending Integration Tests (help wanted)

[AtakanColak]

With #86 we now do support integration tests both in local docker and GitHub Actions, but we need to extend the existing integration tests to cover for most of the functionalities.

Particular Tests

• Creating a Schema With References
• Fetching References of a Schema
• go.mod version compatibility integration test: version in go.mod file is not updated if we use a newer capability, so we need to test that by building in the oldest version in one of the integration tests
• Protobuf, add producer protobuf example #85 can be used for reference