Update Package.swift

Author: muukii

Package.swift

@@ -8,10 +8,12 @@ let package = Package(
     .library(name: "DataSources", targets: ["DataSources"]),
   ],
   dependencies: [
+    .package(url: "https://github.com/ra1028/DifferenceKit.git", from: "1.2.0")
   ],
   targets: [
     .target(
       name: "DataSources",
+      dependencies: ["DifferenceKit"],
       exclude: ["Info.plist"]
     ),
   ]