Add exyte chat

[f3dm76]

• Project Name: Chat
• Project URL: https://github.com/exyte/chat
• Project Description: SwiftUI Chat UI framework with fully customizable message cells, input view, and a built-in media picker
• Why it should be added to awesome-swift: The most easily customizable chat ever
• [x] At least 15 stars (GitHub project)
• [x] Support Swift 5
• [x] Updated contents.json instead of README
• [x] Lib is fully open sourced, written in Swift and not a wrapper over compiled lib
• [x] Description does not say "written in Swift" or variant 🤓

[vpeschenkov]

@f3dm76 thanks!