This fixes issue #189. This is necessary because GitHub actions are going to drop support for Node.js 16. Version 4 uses Node.js 20. See https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/
- Use rust `--no-self-update` flag instead of separate command. - Add an explicit test for the `git` registry, as the sparse registry is now the default.