Release - 0.47.0

[calvincestari]

Biggest changes included in this release:

1. Starscream removed as an external dependency (Refactor websocket implementation directly into ApolloWebSocket #1906)
2. Playground moved into a separate repository (Removes playgrounds from apollo-ios #1905)
3. Fix in ApolloClient to ensure that it passes the callback queue to ApolloStore for clearCache completion blocks (Use the provided callback queue instead of the store's default. #1904)

Pre-release Checklist

• Update the CHANGELOG with all relevant changes since the prior version.
• Update the version in Configuration/Shared/Project-Version.xcconfig
• Run the Documentation Generator as noted in api-reference.md to re-generate documentation from source for all included libraries
• Validate that main builds with a test Swift Package Manager project
• Validate that main builds with a test CocoaPods project
• Validate that main builds with a test Carthage project

[AnthonyMDev]

You are my hero :)

[designatednerd]

https://www.youtube.com/watch?v=0iAzMRKFX3c