ci: update to node 16 (#3990)

See also: https://github.com/nodejs/Release#release-schedule

Author: Daniele TDC

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [10.x, 12.x, 14.x, 15.x]
+        node-version: [12, 14, 16]
 
     steps:
       - uses: actions/checkout@v2