message: Add GitHub documentation
diff: - [Submitting a proposal](./compiler/steering-meeting/submit.md)
  - [How to run the planning meeting](./compiler/steering-meeting/how-to-run-planning.md)
  - [How to run a design meeting](./compiler/steering-meeting/how-to-run-design.md)
  +- [GitHub](./github.md)
  - [Governance](./governance/README.md)
  - [Infrastructure](./infra/README.md)
  - [Other Installation Methods](./infra/other-installation-methods.md)
  