up(build): Changed verstion to `v1.2.3`.

feat(ci): Drafted macOS/Linux/Windows CI.

refactor(build): Updated version number.

feat(readme): Updated documentation for `ConsoleSink` (colors).

feat(readme): Added Level documentation.

Merge pull request #5 from lypitech/fix/bad-file-extension-exception-…

…message-typo

fix: Fixed typo for BadFileExtension exception.

refactor(build): Changed project's description.