DEployment hook no longer needed in CI

Author: Achim Schneider

.github/workflows/docker.yml

@@ -81,10 +81,3 @@ jobs:
       - name: Push version tagged Docker image
         if: github.ref == 'refs/heads/main' && github.repository == 'paritytech/ink-playground'
         run: docker push ${{ secrets.DOCKER_USER_NAME }}/ink-playground:1.0.$BUILD_NUMBER
-
-      - name: Invoke deployment hook
-        if: github.ref == 'refs/heads/main' && github.repository == 'paritytech/ink-playground'
-        uses: distributhor/workflow-webhook@v2
-        env:
-          webhook_url: ${{ secrets.WEBHOOK_URL }}/redeploy
-          webhook_secret: ${{ secrets.WEBHOOK_SECRET }}