Update package to Swift 6.1

Author: danielsaidi

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 6.0
+// swift-tools-version: 6.1
 
 import PackageDescription
 

README.md

@@ -4,7 +4,7 @@
 
 <p align="center">
     <img src="https://img.shields.io/github/v/release/danielsaidi/AppIconKit?color=%2300550&sort=semver" alt="Version" title="Version" />
-    <img src="https://img.shields.io/badge/swift-6.0-orange.svg" alt="Swift 6.0" />
+    <img src="https://img.shields.io/badge/swift-6.1-orange.svg" alt="Swift 6.1" />
     <img src="https://img.shields.io/badge/platform-SwiftUI-blue.svg" alt="Swift UI" title="Swift UI" />
     <a href="https://danielsaidi.github.io/AppIconKit"><img src="https://img.shields.io/badge/documentation-web-blue.svg" alt="Documentation" /></a>
     <a href="https://github.com/danielsaidi/AppIconKit/blob/master/LICENSE"><img src="https://img.shields.io/github/license/danielsaidi/AppIconKit" alt="MIT License" /></a>