Picodi

- Rewrite `helpers.enter` as class-based context manager (now it behaves more predictably)
- Added `registry.touched` property and `registry.clear_touched` method for tracking
dependencies usage (useful for testing)
- Added pytest integration for simpler testing

- Patch dependency tree when resolving dependencies with overrides
- Breaking changes:
- If you try to override a dependency that is already is use in another override, you will get an error

- revert tags

- Now you can mark you dependencies with tags for more granular control over their lifecycle
- Breaking changes:
- Removed `ignore_manual_init` argument from `dependency` decorator
- `lifespan` now has new signature

- `enter` now respects overrides
- `lifespan` is a factory decorator now

- Make `Dependency.__call__` async because FastAPI always runs Picodi deps in threadpool even if they are async
- Rename `Dependency` to `Depends` [internal change]
- Run mypy in tests directory
- Make sure that `inject` doesn't change type of wrapped function (e.g. coroutinefunction, generatorfunction, etc.)
- Added Starlette integration
- Added FastAPI integration
- Breaking changes:
- Return value of `Provide` no longer has `__call__` method