v0.7.0 - Preparing for ruamel-yaml deprecation

What's Changed

• Fix: Generalize YAML libs by @NowanIlfideme in #22
• Closing #21

Honestly, supporting further developments with multi-library support have become cumbersome as ruamel.yaml moves forward. This release shouldn't break anything, but it might as users might have some uses not covered by current test cases. If something breaks, please create an issue and I'll solve ASAP. You can then downgrade to 0.6.* as there is no difference in functionality.

Full Changelog: v0.6.3...v0.7.0