Update Changelog and Readme#219

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akyrtzi merged 2 commits intoswiftlang:masterfrom

akyrtzi:update-changelog-readme

May 13, 2020

Commits on May 13, 2020

[Changelog] Update Changelog.md to include Swift 5.3 changes
akyrtzi
committed
[Readme] Update Readme to mention how to embed the parser library and how to build it for iOS
akyrtzi
committed