Version 0.20.0

Changes:

• ⚠️ type names no longer use namespaces (#248)
• ⚠️ $.NullaryType, $.UnaryType, and $.BinaryType now take an array of supertypes (#236)
• significant performance improvements (#244, #258)
• improvements to various type signatures (#245, #263)
• null and undefined are no longer members of {}, the empty record type (#243)
• error messages for unmatched parameterized type variables are now accurate (#250)
• extractor functions are now allowed to return any foldable structure (#256)
• $.env now includes $.Array2 ($.Unknown) ($.Unknown), $.Type, and $.TypeClass (#267)
• sanctuary-either dependency upgraded from 1.0.x to 1.1.0 (#223)
• sanctuary-type-classes dependency upgraded from 10.0.x to 11.0.x (#259)

Additions:

• $.Descending (#260)
• $.Either (#246)
• $.Fn (#266)
• $.Identity (#261)
• $.Maybe (#246)
• $.Pair (#246)
• $.NamedRecordType (#238)