Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/macos.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: macos-latest
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Get latest ytdl_hook.lua
         run: |