Update auto-update.yml

.github/workflows/auto-update.yml

@@ -376,6 +376,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2
         with:
+          ref: master
           fetch-depth: 0
       - name: Generate Token
         uses: tibdex/github-app-token@v1
@@ -395,7 +396,6 @@ jobs:
           author: 'iptv-bot[bot] <84861620+iptv-bot[bot]@users.noreply.github.com>'
           branch: bot/auto-update
           delete-branch: false
-          base: master
           token: ${{ steps.generate-token.outputs.token }}
       - name: Enable Pull Request Automerge
         if: steps.pr.outputs.pull-request-operation == 'created'