Click-extra

- Temporarily skip displaying environment details in `--version` option results
for `python >= 3.10`.
- Reactivate all tests on Python 3.10.

- Expose some `cloup` versions of `click` utilities at the root of
`click_extra`.

- Allow `click_extra` to be imported as a drop-in replacement for `click`.
- Share the same set of default options between `click_extra.command` and
`click_extra.group`.
- Document default help screen comparison between simple `click` CLI and
enhanced `click-extra` CLI.

- Add support for JSON configuration file.
- Search all supported formats in default location if configuration file not
provided.
- Print configuration file default location in help screens.

- Add new external workflow to modernize Python code.
- Use external workflow suite to manage changelog and build & publish packages
on PyPi on release.
- Use external workflow to label sponsored issues and PRs.
- Replace local workflow by external one to label issues and PRs.
- Reuse externnal workflow to produce dependency graph.
- Remove dev dependencies on `check-wheel-contents`, `graphviz`, `pipdeptree`
and `twine`.

- Allow downloading of a remote config URL.
- Add new dependencies on `requests` and `pytest-httpserver`.
- Fix inference of config file top-level section name.
- Document usage of `click_extra.config.config_option`.
- Use external workflows for GitHub actions.
- Automate version and changelog management.