Getoutline-cli

Fixed

- Updated README.md with correct installation and usage instructions.

Added

- Preview option to display document without publishing.

Fixed

- Fixed `OUTLINE_URL` environment variable description.

Added

- Ability to specify token and URL via environment variables `OUTLINE_API_TOKEN` and `OUTLINE_URL`.

Added

- Initial release of `getoutline-cli` with the following features:
- Publish markdown files to Outline wiki.
- Support for configuration file `.outline-cli.yml`.
- Support for text substitutions using regular expressions.