Fastapi-mqtt

Maintenance update, with minor changes (from 94)

* **Updated examples with `lifespan` usage** (instead of deprecated `.init_app()` method)
* Better typing for decorators
* Increase required Python version to >=3.8 (syncing with fastAPI)
* **Adjust dependencies to work with new `fastapi-slim` package variant**, available since `fastapi>=0.111`

Changes (from https://github.com/sabuhish/fastapi-mqtt/pull/86)

- 🐛 Fix compatibility for Python < 3.10 (https://github.com/sabuhish/fastapi-mqtt/issues/85)
- 🎨 Add typing for message handlers for better IDE integration
- 📝 Evolve example app with more typing and sync with README

(re-released to test GA for pypi publish)

Changes

* 🐛 Fix usage with **shared subscriptions** (from 81, 82)
* ✨ Add explicit async methods for fastapi app lifespan (79)
* ✏️ Fixed typos and better docs (from 73, 74, 76, 80)
* 🎨 Internal changes for linter configuration (now using `pre-commit` and `ruff`) (66)
* 🥚 Add a more complex **example app**, with fastapi lifespan, router, dependencies, websocket endpoint, and more (83)

In this release;
- Pydantic v2 fully supported
- ConfigDict added
- Changes on package classifiers
- Apart from pydantic, dependency libraries have been upgraded (fastapi, gmqtt, mypy)


Thanks to azogue for making the library to be compatible with pydantic's v2

Thanks to awesome contributors keeping this library up.

Changes added by mblo and plundeen;

44 && 47

In this release;
- We are removing the Settings class of pydantic and instead, we are using BaseModel.
- Some minor typo changes applied
- These changes enabled pydandic v2
- Also closes the issue 68 in the repo
- Some formatting applied


Thanks azogue for his work on this PR 69