chore(deps): bump flutter_markdown in /packages/stream_chat_flutter

Bumps [flutter_markdown](https://github.com/flutter/packages/tree/main/packages) from 0.6.23 to 0.7.1.
- [Release notes](https://github.com/flutter/packages/releases)
- [Commits](https://github.com/flutter/packages/commits/flutter_markdown-v0.7.1/packages)

---
updated-dependencies:
- dependency-name: flutter_markdown
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

packages/stream_chat_flutter/pubspec.yaml

@@ -23,7 +23,7 @@ dependencies:
   file_selector: ^1.0.0
   flutter:
     sdk: flutter
-  flutter_markdown: ^0.6.17+1
+  flutter_markdown: ">=0.6.17+1 <0.8.0"
   flutter_portal: ^1.1.4
   flutter_svg: ^2.0.7
   http_parser: ^4.0.2