fix demo

Author: makai410

.github/workflows/demo.yml

@@ -1,4 +1,4 @@
-# Run a job to ensure formatting is OK
+# Run a job to ensure that we can run the demo successfully.
 name: Run demo
 on:
   pull_request:
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Run Demo
         run: ./demo/run_demo.sh