v0.5.0 of retrofit_craft_plugin

craft_runner plugin that generates a grouped, versioned retrofit API client aggregator. Changelog excerpt: - Synchronized release across riverpod_craft_plugin, craft_runner, retrofit_craft, and retrofit_craft_plugin. No functional changes vs 0.4.0 — version bumped to keep the four packages in lock-step going forward. - Internal: riverpod_craft_pluginand craft_runnerconstraints bumped to ^0.5.0.