v0.33.0

Happy new year! Thanks to @nicoburns for these changes, enabling much faster compiles if you don't need the builders!

• Eliminate regex and once_cell dependencies. by @nicoburns in #514
• Make bon builders optional by @nicoburns in #515
• Make options structs exhaustive by @nicoburns in #516

Diff: v0.32.0...v0.33.0