workflows: Upgrade GitHub actions.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

Author: andersk

.github/workflows/node.js.yml

@@ -10,9 +10,9 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: lts/*
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - run: npm ci
       - run: npm test