Run tests on node 14 too

.github/workflows/test.yml

@@ -6,12 +6,15 @@ jobs:
   tests:
     name: Tests
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node: [12, 14]
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v1
         with:
-          node-version: "12.x"
-          registry-url: "https://registry.npmjs.org"
+          node-version: ${{matrix.node}}
       - name: Install deps
         run: yarn
       - name: Lint