docs: add flutter_chat_ui (#903)

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## Description

Add [flutter_chat_ui](https://github.com/flyerhq/flutter_chat_ui) to the
list of projects using melos

## Type of Change

<!--- Put an `x` in all the boxes that apply: -->

- [ ] ✨ `feat` -- New feature (non-breaking change which adds
functionality)
- [ ] 🛠️ `fix` -- Bug fix (non-breaking change which fixes an issue)
- [ ] ❌ `!` -- Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] 🧹 `refactor` -- Code refactor
- [ ] ✅ `ci` -- Build configuration change
- [x] 📝 `docs` -- Documentation
- [ ] 🗑️ `chore` -- Chore

Author: demchenkoalex

docs/index.mdx

@@ -73,6 +73,7 @@ The following projects are using Melos:
 - [StacDev/stac](https://github.com/StacDev/stac)
 - [Jaspr](https://github.com/schultek/jaspr)
 - [starknet.dart](https://github.com/focustree/starknet.dart)
+- [flyerhq/flutter_chat_ui](https://github.com/flyerhq/flutter_chat_ui)
 
 <Info>
 

packages/melos/README.md

@@ -226,6 +226,7 @@ The following projects are using Melos:
 - [StacDev/stac](https://github.com/StacDev/stac)
 - [Jaspr](https://github.com/schultek/jaspr)
 - [starknet.dart](https://github.com/focustree/starknet.dart)
+- [flyerhq/flutter_chat_ui](https://github.com/flyerhq/flutter_chat_ui)
 
 > Submit a PR if you'd like to add your project to the list. Update the
 > [README.md](https://github.com/invertase/melos/edit/main/packages/melos/README.md)