appraisal2 3.1.0: Lifecycle hooks and explicit generation commands

🏷️ release appraisal2 🏷️ 3.1.0

Version 3.1.0 introduces lifecycle hooks, including an in-memory Gemfile transform, and separate generate-install and generate-update commands. Install and update now operate on existing generated Gemfiles. Review CI commands if they previously relied on installation implicitly regenerating those files.

Read the upstream release notes for the complete changes and see the project repository for usage and installation.