Typo in README.md

Snapshot and release registries are inverted in the .docker/config.json example:

{
  "auths": {
    "${docker_snapshot_registry_host}": {
      "auth": "${docker_release_authent_token}"
    },
    "${docker_release_registry_host}": {
      "auth": "${docker_snapshot_authent_token}"
    },
    "my-readonly-repo-to-pull": {
      "auth": "${MY_OWN_REGISTRY_TOKEN}"
    }
  }
}

should be

{
  "auths": {
    "${docker_snapshot_registry_host}": {
      "auth": "${docker_snapshot_authent_token}"
    },
    "${docker_release_registry_host}": {
      "auth": "${docker_release_authent_token}"
    },
    "my-readonly-repo-to-pull": {
      "auth": "${MY_OWN_REGISTRY_TOKEN}"
    }
  }
}