The Docker image `ghcr.io/actions/actions-runner` is missing documentation

[linghengqian]

Describe the bug
A clear and concise description of what the bug is.

• Clicking on https://github.com/actions/runner/pkgs/container/actions-runner reveals that the Docker image ghcr.io/actions/actions-runner has no usage documentation. There is no documentation explaining how to configure or start the Github Runner via the Docker CLI or Docker Compose files. This appears to be a missing item in Provide runner as a Docker Image #367 and Dockerfile and workflow change for runner image #2250 .

To Reproduce
Steps to reproduce the behavior:

1. Go to https://github.com/actions/runner/pkgs/container/actions-runner .

Expected behavior
A clear and concise description of what you expected to happen.

• The Docker image ghcr.io/actions/actions-runner should have proper documentation explaining how to configure or start the Github Runner via the Docker CLI or Docker Compose files.

Runner Version and Platform

Version of your runner?

• https://github.com/actions/runner/releases/tag/v2.334.0

OS of the machine running the runner? OSX/Windows/Linux/...

• Linux

What's not working?

Please include error messages and screenshots.

• 

Job Log Output

If applicable, include the relevant part of the job / step log output here. All sensitive information should already be masked out, but please double-check before pasting here.

• It doesn't seem important.

Runner and Worker's Diagnostic Logs

If applicable, add relevant diagnostic log information. Logs are located in the runner's _diag folder. The runner logs are prefixed with Runner_ and the worker logs are prefixed with Worker_. Each job run correlates to a worker log. All sensitive information should already be masked out, but please double-check before pasting here.

• It doesn't seem important.