Fixes #15: Update for Swift 5.1 toolchain.

- Added build targets
- Added installation instructions to README
- Added library product to package description

Package.swift

@@ -1,3 +1,4 @@
+// swift-tools-version:4.0
 //
 //  Created by Richard Hodgkins on 07/06/2016.
 //  Copyright (c) 2016 Richard Hodgkins. All rights reserved.
@@ -6,5 +7,23 @@
 import PackageDescription
 
 let package = Package(
-  name: "HTTPStatusCodes"
+    name: "HTTPStatusCodes",
+    products: [
+        .library(name: "HTTPStatusCodes", targets: ["HTTPStatusCodes"])
+    ],
+    targets: [
+        .target(
+            name: "HTTPStatusCodes",
+            path: "Sources"
+        ),
+        .testTarget(
+            name: "HTTPStatusCodesTests",
+            dependencies: ["HTTPStatusCodes"],
+            path: "Tests/HTTPStatusCodesTests",
+            sources: [
+                "HTTPStatusCodesTests.swift",
+                "RegressionTests.swift"
+            ]
+        )
+    ]
 )

README.md

@@ -18,11 +18,20 @@ If this library is out of date compared to this page please open an issue and I
 
 ### Swift versions support
 
+* Swift 5.1 - use version 3.3.2
 * Swift 5 - use version 3.3.1
 * Swift 4 - use version 3.3.0
 * Swift 3 - use version 3.1
 * Older versions - use version 3.0
 
+### Swift Package Manager
+
+Add this package to the dependencies in your `Package.swift` file:
+
+```swift
+.package(url: "https://github.com/rhodgkins/SwiftHTTPStatusCodes.git", .upToNextMajor(from: "3.0.0"))
+```
+
 ### Carthage
 
 `Cartfile`: