fix: version is still undefined - use github version for label

[peterpeterparker]

Fcking pain.

❯ docker image inspect --format '{{json .}}' 56ba93701f14 | jq -r '. | {Id: .Id, Digest: .Digest, RepoDigests: .RepoDigests, Labels: .Config.Labels}'
{
  "Id": "sha256:56ba93701f1487a9f7b60d3c53ea1cd49254778bea90bac2b0bff7ce43ae39e0",
  "Digest": null,
  "RepoDigests": [
    "junobuild/skylab@sha256:d3dd9759c599917b2e12007b1b18afa1e46d5916acd933ff4276f8c30006a485"
  ],
  "Labels": {
    "homepage": "https://juno.build",
    "maintainer": "David Dal Busco <david.dalbusco@outlook.com>",
    "org.opencontainers.image.created": "2026-03-14T13:11:00.891Z",
    "org.opencontainers.image.description": "📦 Juno Docker images for local dApp development and E2E tests",
    "org.opencontainers.image.licenses": "MIT",
    "org.opencontainers.image.ref.name": "ubuntu",
    "org.opencontainers.image.revision": "50853818d64966a099868c7063c458c53b41af32",
    "org.opencontainers.image.source": "https://github.com/junobuild/juno-docker",
    "org.opencontainers.image.title": "juno-docker",
    "org.opencontainers.image.url": "https://github.com/junobuild/juno-docker",
    "org.opencontainers.image.version": "", // <-------------- 🤬
    "repository": "https://github.com/junobuild/juno-docker"
  }
}