v0.4.0

Chore: update `context.tf` to `null-label:0.25.0` and run `make github/init`. @korenyoni (#12)

what

• Update context.tf from latest null-label release (0.25.0).
• Run make github/init.

why

• The auto-context workflow did not run because the repository has been inactive for 90 days.
• The latest context.tf allows for using the tenant label.
• Running make github/init updates important files relating to GitHub Actions.

references

• https://github.com/cloudposse/terraform-null-label/releases/tag/0.25.0
• closes #10