remove setup-icu, add running on node 14.x and 16.x

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [12.x]
+        node-version: [12.x, 14.x, 16.x]
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
 
     steps:
@@ -26,5 +26,4 @@ jobs:
       with:
         node-version: ${{ matrix.node-version }}
     - run: npm ci
-    - uses: sarisia/setup-icu@v1
     - run: npm run build-prod