Move to Vitest, Include Types, & More

What's Changed

• Migrate from Jest to Vitest. by @alexmacarthur in #5
• Create LICENSE by @alexmacarthur in #7
• Update docs, update default transition. by @alexmacarthur in #8
• fix types by @alexmacarthur in #9

Full Changelog: v0.0.3...v0.0.4