Add lefthook and bump Ruby version

What does this MR do and why?

This MR adds a few things to improve developer happiness 🙂

Action items

• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review