build(test.yml): set node-version to 16

Author: gr2m

.github/workflows/test.yml

@@ -1,30 +1,31 @@
 name: Test
-on:
+"on":
   push: {}
   pull_request:
-    types: [opened, synchronize]
-
+    types:
+      - opened
+      - synchronize
 jobs:
   integration:
     runs-on: ubuntu-latest
-    # don't run integration tests on push unless it's the main branch
     if: github.event_name == 'pull_request' || github.ref == 'refs/heads/main'
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v2
         with:
           cache: npm
+          node-version: 16
       - run: npm ci
       - run: npm test
   createComment:
     runs-on: ubuntu-latest
-    # only run on push events
     if: github.event_name == 'push'
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v2
         with:
           cache: npm
+          node-version: 16
       - run: npm ci
       - run: node test/fixtures/app.js
         env: