No backported label

It's not working and doesn't help a lot. The main painpoint is bad (conflicting) backports
which it wasn't designed to detect anyway.

.github/workflows/backport.yml

@@ -17,12 +17,5 @@ jobs:
         with:
           bot_username: qgis-bot
           bot_token: ddbdec32940df79f1adf2369b4b10f10b5a66f65
-          bot_token_key: a1b2c3d47311f8e29e204f85a81b4df4a44e252c
+          # bot_token_key: a1b2c3d47311f8e29e204f85a81b4df4a44e252c
           github_token: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Backported Label
-        if: steps.backport.conclusion == 'success'
-        uses: actions-ecosystem/action-add-labels@v1
-        with:
-          github_token: ${{ secrets.github_token }}
-          labels: backported