Bump podspec to version 5.3

Bump podspec to version 5.2

Update Changelog for version 5.1.0

Merge pull request sunshinejr#227 from sunshinejr/release/5.0.0

[Release] 5.0.0

Merge pull request sunshinejr#222 from sunshinejr/release/5.0.0-beta.5

[Release] 5.0.0 beta.5

Merge pull request sunshinejr#219 from sunshinejr/release/5.0.0-beta.4

[Release] 5.0.0 beta.4

Merge pull request sunshinejr#216 from sunshinejr/release/5.0.0-beta.3

[Release] 5.0.0-beta.3

Merge pull request sunshinejr#210 from sunshinejr/release/5.0.0-beta.2

[Release] 5.0.0-beta.2

Update podspec to use 5.0.0-beta.1

[skip ci]

Merge pull request sunshinejr#193 from radex/release/4.0.0

[Release] 4.0.0