Test fixes

This fixes all the issues detected by the ZSchema tests.

Summary:
- One schema issue: `exclusiveMinimum` typo
- One ZSchema issue: email validation was too strict (https://github.com/zaggino/z-schema/issues/48). However, I suggest we use [example.com](example.com) anyways, it was built by ICANN for this exact purpose.
- Several issues with the YAML examples not complying with the schema. See individual commits.