Use Swift 5 in Package.swift

Author: devxoul

Package.swift

@@ -1,9 +1,12 @@
-// swift-tools-version:4.0
+// swift-tools-version:5.0
 
 import PackageDescription
 
 let package = Package(
   name: "RxDataSources",
+  platforms: [
+    .iOS(.v8), .tvOS(.v9)
+  ],
   products: [
     .library(name: "RxDataSources", targets: ["RxDataSources"]),
     .library(name: "Differentiator", targets: ["Differentiator"]),
@@ -15,5 +18,6 @@ let package = Package(
     .target(name: "RxDataSources", dependencies: ["Differentiator", "RxSwift", "RxCocoa"]),
     .target(name: "Differentiator"),
     .testTarget(name: "RxDataSourcesTests", dependencies: ["RxDataSources"]),
-  ]
+  ],
+  swiftLanguageVersions: [.v4_2, .v5]
 )