added package.swift file

Author: msadoon

ReactiveExtensions/Package.swift

@@ -0,0 +1,25 @@
+// swift-tools-version:5.5
+import PackageDescription
+
+let package = Package(
+  name: "ReactiveExtensions",
+  products: [
+    .library(
+      name: "ReactiveExtensions-iOS",
+      targets: ["ReactiveExtensions-iOS"]
+    ),
+    .library(
+      name: "ReactiveExtensions-TestHelpers-iOS",
+      targets: ["ReactiveExtensions-TestHelpers-iOS"]
+    )
+  ],
+  targets: [
+    .target(name: "ReactiveExtensions-iOS"),
+    .testTarget(
+      name: "ReactiveExtensions-iOSTests",
+      dependencies: ["ReactiveExtensions-iOS", "ReactiveExtensions-TestHelpers-iOS"],
+      path: "ReactiveExtensions/tests"
+    ),
+    .target(name: "ReactiveExtensions-TestHelpers-iOS")
+  ]
+)