Support parallel multi-platform container images in ghcr.io

[tillkuhn]

Goal

Build and publish multi-plaform images for linux/amd64 and linux/arm64 as outlined in Multi-platform image with GitHub Actions and Distribute build across multiple runners]
Target registry in ghcr.io, so the images should packages section.

Caveats

All public GitHub Runners are amd64, so the QEMU build for arm64 is really slow (>15). There's a dicussion here, so maybe we see arm runners in future. Shouldn't be a big deal for us, since our releases are rather infrequent

Test

Rancher on MacOS (amd64)

$ docker run --rm ghcr.io/dbschenker/vaultpal:multi-platform-containers version
multi-platform-containers (commit: b938da2), built 2023-09-27T10:49:50Z, platform linux/amd64

Linux arm64

$ ec2-user@ip***** ~]$ docker run --rm ghcr.io/dbschenker/vaultpal:multi-platform-containers version
multi-platform-containers (commit: b938da2), built 2023-09-27T10:50:50Z, platform linux/arm64

Inspect Manifest

docker manifest inspect ghcr.io/dbschenker/vaultpal:multi-platform-containers
{
   "schemaVersion": 2,
   "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
   "manifests": [
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 2260,
         "digest": "sha256:b04412326b0ed2afe081aeb3a2b77ecd0d817a7b837f2bfa55a5a32d0d5337cc",
         "platform": {
            "architecture": "arm64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 2260,
         "digest": "sha256:fafdeecdf53ee4abda93d6c063dfd8f1ca5cfee4dc7b6b17f8d694fb02ec713a",
         "platform": {
            "architecture": "amd64",
            "os": "linux"
         }
      }
   ]
}

[pschulten]

to the galaxy and beyond!