Add schedule to workflow

In a GitHub action we can add the schedule key to run a workflow at
a specific time.

We are adding a new workflow to run the 'Build with latest Expo' script.
In this case we will run the workflow every day at midnight UTC.

.github/workflows/scheduled_expo_build.yml

@@ -0,0 +1,24 @@
+name: Belt CI
+
+on:
+  schedule:
+    - cron: '0 0 * * *'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [18.x, 20.x]
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Install dependencies
+        run: yarn --frozen-lockfile
+      - name: Build with latest Expo
+        run: node bin/checks/build-with-latest-expo.check.js