4.0.0

Breaking

• Swift 5.1 or later is now required to build Yams.
  JP Simard

Enhancements

• YAMLDecoder now conforms to the TopLevelDecoder protocol when
  Apple's Combine framework is available.
  JP Simard
  #261

• Add YAMLDecoder.decode(...) overload tha takes a YAML string encoded
  as Data using UTF8 or UTF16.
  JP Simard

Bug Fixes

• Fix CMake installation issues.
  Saleem Abdulrasool