Bump version to 2.2.0

Author: onevcat

APNGKit.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name         = "APNGKit"
-  s.version      = "2.1.2"
+  s.version      = "2.2.0"
   s.summary      = "High performance and delightful way to play with APNG format in iOS."
 
   s.description  = <<-DESC

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+## [2.2.0] - 2022-03-12
+
 ### Add
 
 - Support for setting a single `APNGImage` to multiple `APNGImageView`s. It lifts off the limitation in previous versions that an `APNGImage` can only be set to one `APNGImageView`. Now, it is free to be used in different image views and the image view controls the animation playing. [#124](https://github.com/onevcat/APNGKit/pull/124) @onevcat
@@ -53,3 +55,4 @@ need also check the README to do a re-implement.
 [2.1.0]: https://github.com/onevcat/APNGKit/compare/2.0.2...2.1.0
 [2.1.1]: https://github.com/onevcat/APNGKit/compare/2.1.0...2.1.1
 [2.1.2]: https://github.com/onevcat/APNGKit/compare/2.1.1...2.1.2
+[2.2.0]: https://github.com/onevcat/APNGKit/compare/2.1.2...2.2.0