feat: add multi-architecture (ARM64) support for rollouts-demo images

[tbernacchi]

Add Multi-Architecture Support for Rollouts Demo Images

What changes are being made?

• Added GitHub Actions workflow for building multi-arch images
• Added support for ARM64 architecture
• Added build script for generating all variants

Why are these changes needed?

The current rollouts-demo images only support AMD64, making it impossible to run the demo on ARM-based systems like M1/M2 Macs or Raspberry Pi.

How to verify it?

1. The workflow will build images for both AMD64 and ARM64;
2. Images can be tested on different architectures;
3. No changes to existing functionality.

Setup

Required Secrets:
DOCKERHUB_TOKEN: Docker Hub access token
Environment variables (configured in workflow):

Usage

Automatic Execution

The workflow runs automatically on:

• Push to main
• Pull Requests to main

Manual Execution

• Go to "Actions" tab
• Select "Build and Push Multi-Arch Rollouts Demo Images"
• Click "Run workflow"
• Select branch
• Click "Run workflow"

Notes to reviewers

• The current images won't be overwritten until approved
• We can use a different registry/tag for testing
• Can be merged after verification on different architectures

[meeech]

Q: Why not just fix the current Makefile build command to produce for each platform?

[tbernacchi]

I'm not sure, this setup worked in my environment, so I decided to contribute it in case it's useful.