4.1.1

• Update the README with up-to-date Swift versions and Installation Instructions.
  @kuyazee
  @AliSoftware
  #95

• Set APPLICATION_EXTENSION_API_ONLY build setting on built frameworks.
  @AliSoftware
  #98
  @nahung89
  #88

• Update tools used by the project (Xcode, CocoaPods, CI, Carthage).
  Also SPM builds are now tested by CI.
  @AliSoftware
  #97

• Update SPM Package.swift to mention supported platforms.
  @MortyMerr
  #89
  @pahnev
  #93
  @mackoj
  #85

• Fix nib name lookup when using subclassing.
  @calmez
  #96