use node v16 in test runner

Author: tjjfvi

.github/workflows/main.yml

@@ -13,10 +13,10 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             - uses: actions/checkout@v1
-            - name: install node v12
+            - name: install node v16
               uses: actions/setup-node@v1
               with:
-                  node-version: 12
+                  node-version: 16
 
             - name: yarn install
               run: yarn install