Remove SwiftSerial dependency.

Package.swift

@@ -6,21 +6,16 @@ import PackageDescription
 let package = Package(
     name: "SwiftRPLidar",
     products: [
-        // Products define the executables and libraries produced by a package, and make them visible to other packages.
         .library(
             name: "SwiftRPLidar",
             targets: ["SwiftRPLidar"]),
     ],
     dependencies: [
-        // Dependencies declare other packages that this package depends on.
-        .package(url: "https://vato.ddns.net/gitlab/vato007/SwiftSerial.git", .branch("dtr_support"))
     ],
     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: "SwiftRPLidar",
-            dependencies: [.product(name: "SwiftSerial", package: "SwiftSerial")]),
+            dependencies: []),
         .testTarget(
             name: "SwiftRPLidarTests",
             dependencies: ["SwiftRPLidar"]),