CI should test on Node 16; update Node CI action

See [#313][0].

[0]: #313

Author: Fdawgs

.github/workflows/nodejs.yml

@@ -8,11 +8,11 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [10.x, 12.x, 14.x]
+        node-version: [10.x, 12.x, 14.x, 16.x]
 
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
+      - uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node-version }}
       - run: npm ci