Latest (v2.311.0-ubuntu-20.04-8e48463) Summerwind runner image is missing docker buildx

Checks

• I've already read https://github.com/actions/actions-runner-controller/blob/master/TROUBLESHOOTING.md and I'm sure my issue is not covered in the troubleshooting guide.
• I'm not using a custom entrypoint in my runner image

Controller Version

27.5

Helm Chart Version

actions-runner-controller-0.23.5

CertManager Version

v1.13.1

Deployment Method

Helm

cert-manager installation

Cert manager is fine

Checks

• This isn't a question or user support case (For Q&A and community support, go to Discussions. It might also be a good idea to contract with any of contributors and maintainers if your business is so critical and therefore you need priority support
• I've read releasenotes before submitting this issue and I'm sure it's not due to any recently-introduced backward-incompatible changes
• My actions-runner-controller version (v0.x.y) does support the feature
• I've already upgraded ARC (including the CRDs, see charts/actions-runner-controller/docs/UPGRADING.md for details) to the latest and it didn't fix the issue
• I've migrated to the workflow job webhook event (if you using webhook driven scaling)

Resource Definitions

..

To Reproduce

- name: Build Docker Image
  shell: bash
  env:
      DOCKER_BUILDKIT: "1"
  run: |
    docker build .

Describe the bug

This fails with:

ERROR: BuildKit is enabled but the buildx component is missing or broken.

Looks like there was a PR yesterday that upped the docker version and now we need the same fix as went into the Github runner image here:

https://github.com/actions/runner/pull/2901

Rolling back to ummerwind/actions-runner:v2.311.0-ubuntu-20.04-fb11d3b fixes the issue.

Describe the expected behavior

The docker build works.

Whole Controller Logs

n/a

Whole Runner Pod Logs

n/a

Additional Context

n/a

Start by inspecting how the Summerwind runner image v2.311.0-ubuntu-20.04-8e48463 is built, then compare its Docker setup with the referenced actions/runner PR 2901. Reproduce the failure using DOCKER_BUILDKIT=1 and the provided docker build workflow; done means the runner image builds successfully with Docker buildx available.