Update package name (#555)

* Update package name

* wip

Author: stephencelis

Package.swift

@@ -3,7 +3,7 @@ import Foundation
 import PackageDescription
 
 let package = Package(
-  name: "SnapshotTesting",
+  name: "swift-snapshot-testing",
   platforms: [
     .iOS(.v11),
     .macOS(.v10_10),

README.md

@@ -143,16 +143,25 @@ If you want to use SnapshotTesting in any other project that uses [SwiftPM](http
 
 ```swift
 dependencies: [
-  .package(name: "SnapshotTesting", url: "https://github.com/pointfreeco/swift-snapshot-testing.git", from: "1.9.0"),
+  .package(
+    url: "https://github.com/pointfreeco/swift-snapshot-testing.git",
+    from: "1.9.0"
+  ),
 ]
 ```
 
 Next, add `SnapshotTesting` as a dependency of your test target:
 
 ```swift
 targets: [
-  .target(name: "MyApp", dependencies: [], path: "Sources"),
-  .testTarget(name: "MyAppTests", dependencies: ["MyApp", "SnapshotTesting"])
+  .target(name: "MyApp"),
+  .testTarget(
+    name: "MyAppTests",
+    dependencies: [
+      "MyApp",
+      .product(name: "SnapshotTesting", package: "swift-snapshot-testing"),
+    ]
+  )
 ]
 ```