add back daily cronjob

.github/workflows/nightly.yml

@@ -0,0 +1,43 @@
+name: Nightly test
+
+on:
+  schedule:
+    - cron: '0 0 * * *'
+  workflow_dispatch:
+
+jobs:
+  nightly-test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Get Polkadot and Staking Miner Playground binaries
+        uses: ./.github/workflows/actions/prepare-binaries
+
+      - name: Cache Rust dependencies
+        uses: swatinem/rust-cache@v2
+        with:
+          key: ${{ runner.os }}-rust-${{ hashFiles('**/Cargo.lock') }}
+          cache-on-failure: true
+
+      - name: Run nightly tests
+        run: |
+          RUST_LOG=info cargo test --workspace --all-features -- --nocapture
+
+      - name: Create an issue on failure
+        if: failure()
+        uses: JasonEtco/create-an-issue@v2
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          FAILED_WORKFLOW_RUN_URL: https://github.com/${{ github.repository }}/commit/${{ github.sha }}/checks/${{ github.run_id }}
+        with:
+          # Use this issue template:
+          filename: .github/issue_templates/nightly_run_failed.md
+          # Update existing issue if found; hopefully will make it clearer
+          # that it is still an issue:
+          update_existing: true
+          # Look for new *open* issues in this search (we want to
+          # create a new one if we only find closed versions):
+          search_existing: open
+