Remove labels from names and URLs in lockfile

[egibs]

Addresses https://github.com/chainguard-dev/apko/issues/1052.

This PR removes the @label portion of the URI string so that the lockfile doesn't cause the errors noted in the above issue.

Comparison: Before:

{
    "version": "v1",
    "config": {
      "name": "examples/label.yaml",
      "checksum": "sha256-MlNjWrkMHwpre/9kkrDCXU2+y/pzyD4DMZgdc97ymk4="
    },
    "contents": {
      "keyring": [
        {
          "name": "packages.wolfi.dev/os/wolfi-signing.rsa.pub",
          "url": "https://packages.wolfi.dev/os/wolfi-signing.rsa.pub"
        }
      ],
      "repositories": [
        {
          "name": "@wolfi https://packages.wolfi.dev/os/x86_64",
          "url": "@wolfi https://packages.wolfi.dev/os/x86_64/APKINDEX.tar.gz",
          "architecture": "x86_64"
        },
        {
          "name": "@wolfi https://packages.wolfi.dev/os/aarch64",
          "url": "@wolfi https://packages.wolfi.dev/os/aarch64/APKINDEX.tar.gz",
          "architecture": "aarch64"
        }
      ],
      "packages": []
    }
  }

After:

{
  "version": "v1",
  "config": {
    "name": "examples/label.yaml",
    "checksum": "sha256-MlNjWrkMHwpre/9kkrDCXU2+y/pzyD4DMZgdc97ymk4="
  },
  "contents": {
    "keyring": [
      {
        "name": "packages.wolfi.dev/os/wolfi-signing.rsa.pub",
        "url": "https://packages.wolfi.dev/os/wolfi-signing.rsa.pub"
      }
    ],
    "repositories": [
      {
        "name": "https://packages.wolfi.dev/os/x86_64",
        "url": "https://packages.wolfi.dev/os/x86_64/APKINDEX.tar.gz",
        "architecture": "x86_64"
      },
      {
        "name": "https://packages.wolfi.dev/os/aarch64",
        "url": "https://packages.wolfi.dev/os/aarch64/APKINDEX.tar.gz",
        "architecture": "aarch64"
      }
    ],
    "packages": []
  }
}

make test and make lint pass with these changes.

[egibs]

cc: @jonjohnsonjr