Snk

Add `require_conda` option to snk config and only use conda if it is available.

Solves https://github.com/Wytamma/snk/issues/45

**Full Changelog**: https://github.com/Wytamma/snk/compare/v0.15.0...v0.16.0

🐛 Fixed --dag error 43

**Full Changelog**: https://github.com/Wytamma/snk/compare/v0.14.0...v0.15.0

What's Changed
* Script command by Wytamma in https://github.com/Wytamma/snk/pull/46
* [✨ add short flags](https://github.com/Wytamma/snk/commit/221bf556daa06628c2cf551cd47093ab94043e74)
* [✨ use cli instead of annotations in snk.yaml](https://github.com/Wytamma/snk/commit/6982665dbbbc00c3091494326086288ecc3c6bb1)
* [✨ version from snk.yml](https://github.com/Wytamma/snk/commit/5b87859a42947cabbcba1464ba1ea6c90c48dc6b)

**Full Changelog**: https://github.com/Wytamma/snk/compare/v0.13.0...v0.14.0

**Full Changelog**: https://github.com/Wytamma/snk/compare/v0.12.2...v0.13.0

**Full Changelog**: https://github.com/Wytamma/snk/compare/v0.12.1...v0.12.2

**Full Changelog**: https://github.com/Wytamma/snk/compare/v0.12.0...v0.12.1