sqlite-utils 4.2.1

Fixes a crashing bug in sqlite-utils 4.2. I'd introduced code that looks like this:

from typing_extensions import Self

It turned out the typing-extensions package was not listed as a dependency for sqlite-utils - it was installed by one of the other dependencies in the dev dependency group, but when you uvx sqlite-utils directly you don't get those dependencies.

As part of fixing this I figured out how to run a smoke test to ensure the CLI tool still works even without those dev dependencies, which can be run from the project checkout:

uv run --isolated --no-default-groups sqlite-utils --help

The --no-default-groups argument prevents it from installing that default dev group, and --isolated means that even if there is a .venv/ folder containing extra dependencies they will be ignored for the duration of that uv run command.