Update Package.swift

Package.swift

@@ -1,10 +1,31 @@
-// swift-tools-version:3.1
+// swift-tools-version:4.0
+// The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
 
 let package = Package(
     name: "SwiftZip",
+    products: [
+        // Products define the executables and libraries produced by a package, and make them visible to other packages.
+        .library(
+            name: "SwiftZip",
+            targets: ["SwiftZip"]),
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        // .package(url: /* package url */, from: "1.0.0"),
+    ],
     targets: [
-        Target(name: "SwiftZip", dependencies: ["Cminizip"])
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages which this package depends on.
+        .target(
+            name: "SwiftZip",
+            dependencies: ["Cminizip"]),
+        .target(
+            name: "Cminizip",
+            dependencies: []),
+        .testTarget(
+            name: "SwiftZipTests",
+            dependencies: ["SwiftZip"]),
     ]
 )