Fix decoding Swift 5.9 package content

[marinofelipe]

A fix for decoding a package dump in Swift 5.9, it ensures that dependencies are correctly decoded

swift 5.9

"dependencies" : [
    {
      "sourceControl" : [
        {
          "identity" : "swift-snapshot-testing",
          "location" : {
            "remote" : [
              {
                "urlString" : "https://github.com/pointfreeco/swift-snapshot-testing"
              }
            ]
          },

before

"dependencies" : [
    {
      "sourceControl" : [
        {
          "identity" : "swift-snapshot-testing",
          "location" : {
            "remote" : [
                "https://github.com/pointfreeco/swift-snapshot-testing"
            ]
          },