ci: test on node 16

Author: isaacs

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ jobs:
   build:
     strategy:
       matrix:
-        node-version: [10.x, 12.x, 14.x, 15.x]
+        node-version: [10.x, 12.x, 14.x, 16.x]
         platform:
         - os: ubuntu-latest
           shell: bash