Improve readme

Author: florianpircher

README.md

@@ -1,25 +1,24 @@
 # Clibgit2 – Swift Package for libgit2
 
-This is a Swift package for linking to the [libgit2](https://libgit2.org) library.
-macOS is currently the only supported platform given the build configuration in the package manifest.
-
-This package does not provide any Swift API overlay and instead just offers access to the C API.
+This Swift package provides access to the libgit2 C API without any Swift API overlay.
 
 ## Usage
 
 Include this package as a dependency like so:
 
 ```swift
 let package = Package(
-	// ...
-	platforms: [
-		.macOS(.v11),
-	],
 	// ...
 	dependencies: [
 		.package(url: "https://github.com/Formkunft/Clibgit2", from: "1.9.0"),
 	],
-	// ...
+	targets: [
+		.target(
+			// ...
+			dependencies: [
+				"Clibgit2",
+			]),
+	]
 )
 ```