feat: Added support for Node 16 (#588)

* feat: Added support for Node 16

* fix: run both npm 6 and 8

.github/workflows/ci.yml

@@ -1,4 +1,3 @@
----
 name: ci
 on:
   push:
@@ -6,23 +5,30 @@ on:
     - master
   pull_request:
 jobs:
-  build:
+  tests:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version:
-        - 12
+        node: [12, 14, 16]
+        npm: [6, 8]
         npm-test:
         - i18n_extract
         - is-es5
         - lint
         - test
+        exclude:
+          - node: 12
+            npm: 8
+          - node: 14
+            npm: 8
+          - node: 16
+            npm: 6
     steps:
     - uses: actions/checkout@v2
     - uses: actions/setup-node@v2
       with:
-        node-version: ${{ matrix.node-version }}
-    - run: npm install -g npm@6
+        node-version: ${{ matrix.node }}
+    - run: npm install -g npm@${{ matrix.npm }}
     - run: make requirements
     - run: make test NPM_TESTS=build
     - run: make test NPM_TESTS=${{ matrix.npm-test }}