chore(deps): bump socketioxide to v0.15.1

[Totodore]

Bump socketioxide to v0.15.1

The new version contains multiple new features :

• The socketio parser system has been reworked. Users can now directly embed binaries into the structs they are serializing/deserializing at any level.
• New custom compiler errors for bad user-provided handlers. It allows to have a more developer friendly experience with socketioxide.
• Fix some protocol minor issues.

Therefore the parser feature contain breaking change:
Here is a migration guide that you may give to loco users somewhere ? Or republish in your discussions.
Totodore/socketioxide#384

I will also propose a PR to update the https://github.com/loco-rs/chat-rooms example.