chore: FFmpeg bump version to n8.1.1 (#72)

Co-authored-by: cxfksword <718792+cxfksword@users.noreply.github.com>

Author: github-actions[bot]

README.md

@@ -1,7 +1,7 @@
 # MPVKit
 
 [![mpv](https://img.shields.io/badge/mpv-v0.41.0-blue.svg)](https://github.com/mpv-player/mpv)
-[![ffmpeg](https://img.shields.io/badge/ffmpeg-n8.1-blue.svg)](https://github.com/FFmpeg/FFmpeg)
+[![ffmpeg](https://img.shields.io/badge/ffmpeg-n8.1.1-blue.svg)](https://github.com/FFmpeg/FFmpeg)
 [![license](https://img.shields.io/github/license/mpvkit/MPVKit)](https://github.com/mpvkit/MPVKit/main/LICENSE)
 
 > MPVKit is only suitable for learning `libmpv` and will not be maintained too frequently.

Sources/BuildScripts/XCFrameworkBuild/main.swift

@@ -50,7 +50,7 @@ enum Library: String, CaseIterable {
         case .libmpv:
             return "v0.41.0"
         case .FFmpeg:
-            return "n8.1"
+            return "n8.1.1"
         case .openssl:
             return "3.3.5"
         case .gnutls: