Add ESP32 PWMOutput support

Package.swift

@@ -13,13 +13,14 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/uraimo/SwiftyGPIO.git", from: "1.2.5"),
+        .package(url: "https://vato.ddns.net/gitlab/vato007/SwiftSerial.git", .branch("master"))
     ],
     targets: [
         // 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: "Swift2dCar",
-            dependencies: ["SwiftyGPIO"]),
+            dependencies: ["SwiftyGPIO", "SwiftSerial"]),
         .testTarget(
             name: "Swift2dCarTests",
             dependencies: ["Swift2dCar"]),