3.0.0-M3

Focus Macro

• add support for tuple field selection (#1095) @kenbot
• withDefault feature, remove Eq constraint (#1094) @kenbot
• at, index features (#1081) @kenbot
• use KeywordContext to restrict Focus syntax (#1079) @kenbot

API changes

• inheritance between optics (#1088) @julien-truffaut
• add Focus[X]() and .focus() to generate Iso/ApplyIso (#1098) @julien-truffaut
• generalise Traversal.applyN to take Optionals (#1100) @julien-truffaut
• remove At instance for tuples, use Focus on tuples instead (#1096) @julien-truffaut
• improve Iso.id composition performance (#1099) @julien-truffaut