Update dependencies (projectwallace#48)

* add Node 16 to CI test matrix

* Update devDependencies, except ava

Author: bartveneman

.github/workflows/test.yml

@@ -15,7 +15,7 @@ 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