v0.24.0

Improve extension mechanism for authorizing new specs

⭐ Enhancements

• Add AnyAttr to go3mf.Triangle
• Reduce allocations while decoding 3mf files
• spec.Error.String() has been improved to be more readable
• Spec error handling has been simplified
• Spec encoding/decoding design has been improved and simplified, also reducing memory allocations

⚠️ Breaking changes

• Move go3mf.Any and go3mf.AnyAttr to spec package
• Move go3mf.Register to spec package
• Move several slices to a struct container so their are better aligned with the 3mf spec and can contain spec.AnyAttr and spec.Any elements
• Spec authoring API has been completely redesigned