v0.3.0

DiffDRR is now built using nbdev as the backend! Main advantage: there's now a functional docs site: https://vivekg.dev/DiffDRR

What's Changed

• Make default DiffDRR dtype torch.float32 by @eigenvivek in #123
• Implement with nbdev by @eigenvivek in #126

Full Changelog: v0.2.3...v0.3.0