Announcing the new `group` step type

Buildkite has introduced a new group step type that allows teams with large and complex pipelines to better organize their pipeline structure. The group step displays steps in logical groupings, improving visual clarity and allowing for more control over pipeline flows. This feature can be useful for organizing package security audits, among other use cases. Additionally, the optional depends_on attribute creates dependencies between collections of steps, optimizing performance and diagnostics. For more information, refer to the documentation.