Bump version: 2.2.0

This version drops support for extremely old platforms and annotates the
library as being explicitly extension safe.

Not marking this as a breaking change because the old platforms are _so_ old
that Xcode itself wasn't actually supporting them anymore either.

Bump version: 2.1.0

This version explicitly adds support for Swift 5

Bump version: 2.0

Version 2.0 drops support for iOS 8

Exposing formattingCharacterSet as a public property on String.Template

Bump version: 1.0.2

This is just a CocoaPods bugfix to add the swift_version to the podspec

Merge pull request #3 from efirestone/firestone/bump-spec

Bump pod version

Initial Commit