remove fly staging deployment action

.github/workflows/fly-deploy-staging.yml

@@ -1,29 +0,0 @@
-
-name: Fly Deploy (staging)
-
-on:
-  workflow_run:
-    workflows: ["Publish to ghcr (staging)"]
-    types:
-      - completed
-
-jobs:
-  deploy:
-    name: Deploy staging app
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-        with:
-          submodules: 'true'
-          ref: v3
-
-      - name: Use flyctl
-        uses: superfly/flyctl-actions/setup-flyctl@master
-
-      - name: Deploy to fly.io
-        run: |
-          cd $GITHUB_WORKSPACE/staging
-          flyctl deploy --local-only
-        env:
-          FLY_API_TOKEN: ${{ secrets.FLY_STAGING_DEPLOY_TOKEN }}