Update to Vapor 4

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:4.0
+// swift-tools-version:5.2
 import PackageDescription
 
 let package = Package(
@@ -8,12 +8,15 @@ let package = Package(
     ],
 	dependencies: [
         // 💧 A server-side Swift web framework.
-        .package(url: "https://github.com/vapor/vapor.git", from: "3.0.0"),
+        .package(url: "https://github.com/vapor/vapor.git", from: "4.3.0"),
 
         // 🤐 Unzip archives
         .package(url: "https://github.com/microtherion/ZIPFoundation.git", from: "0.9.9-µ5")
     ],
     targets: [
-        .target(name: "GzipMiddleware", dependencies: ["Vapor", "ZIPFoundation"]),
+        .target(name: "GzipMiddleware", dependencies: [
+	    .product(name: "Vapor", package: "vapor"),
+	    .product(name: "ZIPFoundation", package: "ZIPFoundation"),
+	])
     ]
 )