Add SPM instructions

README.md

@@ -10,15 +10,15 @@ The current Swift-Sodium documentation is not great. Your help to improve it and
 
 ## Usage
 
-Add `Sodium.framework` as a dependency to your project, and import the module:
+To add Swift-Sodium as dependency to your Xcode project, select `File` > `Swift Packages` > `Add Package Dependency`, enter its repository URL: `https://github.com/jedisct1/swift-sodium.git` and import `Sodium` (explicitly importing `Clibsodium` in addition to it is not required).
+
+Then, to use it in your source code, add:
 
 ```swift
 import Sodium
 ```
 
-The Sodium library itself doesn't have to be installed on the system: the repository already includes a precompiled library for armv7, armv7s, arm64, as well as for the iOS simulator.
-
-It targets Swift 5, introduced in Xcode 10.2.
+The Sodium library itself doesn't have to be installed on the system: the repository already includes a precompiled library for armv7, armv7s, arm64, as well as for the iOS simulator, WatchOS and Catalyst.
 
 The 'Clibsodium.xcframework' framework has been generated by the
 [dist-build/ios.sh](https://github.com/jedisct1/libsodium/blob/master/dist-build/apple-xcframework.sh)