fix: resolve Docker build workflow warnings

[derrix060]

Summary

• Add artifact-metadata: write permission to all Docker build/promote workflows and examples (new GA permission since Jan 2026)
• Bump github-action-image-build-and-push to pick up the actions/cache v4→v5 update (fixes Node.js 20 deprecation warning)
• Add missing permissions block to promote workflows that use actions/attest-build-provenance

Fixes warnings from: https://github.com/NethermindEth/angkor-platform-api/actions/runs/24246678153

Test plan

• Verify Docker build workflow runs without artifact-metadata:write warning
• Verify no "Failed to create storage record" error
• Verify no Node.js 20 deprecation warning for actions/cache

[Copilot]

Pull request overview

Updates Docker-related GitHub Actions workflows (and example consumers) to eliminate new GitHub warnings by adjusting permissions and refreshing the pinned image build/push action.

Changes:

• Add artifact-metadata: write to permissions in Docker build and promote workflows (and example workflows) to address new fine-grained permission requirements.
• Add missing top-level permissions blocks to reusable “promote” workflows that generate attestations.
• Bump NethermindEth/github-action-image-build-and-push pin to a newer commit to pick up upstream dependency updates (incl. cache action update).

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
examples/docker/promote-jfrog.yml	Adds artifact-metadata: write permission to the example promotion workflow.
examples/docker/promote-dockerhub.yml	Adds artifact-metadata: write permission to the example promotion workflow.
examples/docker/docker-push-multiple-jfrog.yaml	Adds artifact-metadata: write permission to the multi-image JFrog example.
examples/docker/build-push-jfrog-simple.yml	Adds artifact-metadata: write permission to the simple JFrog build example.
examples/docker/build-push-jfrog-complete.yml	Adds artifact-metadata: write permission to the complete JFrog build example.
examples/docker/build-push-dockerhub-simple.yml	Adds artifact-metadata: write permission to the simple Docker Hub build example.
examples/docker/build-push-dockehub-complete.yml	Adds artifact-metadata: write permission to the complete Docker Hub build example.
.github/workflows/docker-promote-jfrog.yaml	Adds explicit top-level permissions for promotion + attestations.
.github/workflows/docker-promote-dockerhub.yaml	Adds explicit top-level permissions for promotion + attestations.
.github/workflows/docker-build-push-jfrog.yaml	Adds artifact-metadata: write and bumps the pinned image build/push action commit.
.github/workflows/docker-build-push-dockerhub.yaml	Adds artifact-metadata: write and bumps the pinned image build/push action commit.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

inputs.skip_attest is declared as type: string but its default is the boolean false, and later the workflow compares it to the string 'true'. This type/default mismatch can cause reusable-workflow validation errors or unexpected coercion. Consider making skip_attest a boolean input (with default: false) and updating the if: expression accordingly, or keep it as a string and quote the default (e.g. "false") and document accepted values.

Suggested change

	default: false
	default: "false"