Added vapor's swift-nio-http-client until the official one get tagged…

… and other clean up.

.gitignore

@@ -4,3 +4,4 @@
 /*.xcodeproj
 Package.pins
 Package.resolved
+/.swiftpm

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.0
+// swift-tools-version:5.1
 import PackageDescription
 
 let package = Package(
@@ -8,7 +8,7 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-nio.git", from: "2.0.0"),
-        .package(url: "https://github.com/swift-server/swift-nio-http-client.git", .branch("master"))
+        .package(url: "https://github.com/vapor/swift-nio-http-client.git", from: "0.0.0")
     ],
     targets: [
         .target(name: "StripeKit", dependencies: ["NIOHTTPClient", "NIOFoundationCompat"]),