Update Package.swift and cleanup unused files

Author: dominik-hadl

Package.swift

@@ -5,6 +5,7 @@ import PackageDescription
 
 let package = Package(
     name: "KeyboardHelper",
+    platforms: [ .iOS(.v8) ],
     products: [
         // Products define the executables and libraries produced by a package, and make them visible to other packages.
         .library(
@@ -23,6 +24,7 @@ let package = Package(
             dependencies: []),
         .testTarget(
             name: "KeyboardHelperTests",
-            dependencies: ["KeyboardHelper"]),
+            dependencies: ["KeyboardHelper"],
+            path: "KeyboardHelperTests/Tests"),
     ]
 )