0.6.0

Enhancements

• Add support for task composition with new sequence and ref tasks types
• Add support for hard coded literal arguments to the target callable of script tasks
• Switch to tomlkit for toml parsing to get support for multiline task context (e.g. shell scripts) with dotted paths
• Make shell tasks raise an error if extra arguments are provided (since there's nothing constructive to do with them)
• Improved support for multiline shell tasks on windows