Update swift tools version to 5.7

Added swift package manager support (#1)

* Added swift package manager support

* Try excluding KVOController.h

* Try importing in different way

* Remove exclude option

KVOController 1.2.0 🔑 (facebookarchive#118)

Merge pull request facebookarchive#103 from facebook/nlutsenko.110

KVOController 1.1.0 🔑

increment podspec version; ready v1.0.3 release

increment podspec version; ready v1.0.2 release

tag v1.0.1 release

reference tag