add update action file

.github/workflows/sync_update.yml

@@ -0,0 +1,35 @@
+name: Sync and Update ipv6.m3u
+
+on:
+  schedule:
+    - cron: '0 0 * * *' # 每天一次同步
+  workflow_dispatch:
+
+jobs:
+  sync-and-update:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+        with:
+          ref: main
+
+      - name: Set up Git
+        run: |
+          git config --local user.name "github-actions[bot]"
+          git config --local user.email "github-actions[bot]@users.noreply.github.com"
+          git remote add upstream https://github.com/fanmingming/live.git
+          git fetch upstream
+      - name: Get upstream latest branch
+        run: |
+          git checkout upstream/main -- tv/m3u/ipv6.m3u
+      - name: Replace text in ipv6.m3u
+        run: |
+          sed -i 's/PLTV/TVOD/g' tv/m3u/ipv6.m3u
+      - name: Commit changes
+        run: |
+          git add .
+          git commit -m 'Update ipv6.m3u: Replace PLTV with TVOD'
+          git push -f origin main
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}