Switch tests from Node 15 to Node 16

Author: justingrant

.github/workflows/test.yml

@@ -9,9 +9,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: use node.js v15.x
+      - name: use node.js v16.x
         uses: actions/setup-node@v1
         with:
-          node-version: 15.x
+          node-version: 16.x
       - run: npm ci --no-optional
       - run: npm test

test/intl.mjs

@@ -305,7 +305,7 @@ describe('Intl', () => {
           'japanese: 1/1/12 H\n' +
           'persian: 10/11/1378 AP\n' +
           'roc: 1/1/89 Minguo',
-        node15:
+        node16:
           'iso8601: 1/1/2000\n' +
           'buddhist: 1/1/2543 BE\n' +
           'chinese: 11/25/1999\n' +
@@ -369,7 +369,7 @@ describe('Intl', () => {
           'japanese: 1/3/-643 Taika (645–650)\n' +
           'persian: 10/11/-621 AP\n' +
           'roc: 1/3/1911 Before R.O.C.',
-        node15:
+        node16:
           'iso8601: 1/1/1\n' +
           'buddhist: 1/3/544 BE\n' +
           'chinese: 11/21/0\n' +