Add NodeJS CI GitHub workflow

Refs #1.

Forked from https://github.com/actions/starter-workflows/blob/6adb515f324bc8ef4c0091053438298bbc34a85a/ci/node.js.yml.

Modified this slightly to use Lerna for the dependency management piece. I wasn't able to find any explicit documentation for `npm ci`-like behavior for Lerna, but this appears to be implemented. Looking through lerna/lerna#1360, it appears to support `--ci`.

.github/workflows/nodejs.yml

@@ -0,0 +1,29 @@
+# This workflow will do a clean install of node dependencies, build the source code and run tests across different versions of node
+# For more information see: https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
+
+name: Node.js CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [ 12.x ]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup Node.js
+      uses: actions/setup-node@v1
+      with:
+        node-version: 12.x
+    - run: npm ci
+    - run: npm run -- lerna bootstrap --ci
+    - run: npm run -- lerna run build
+    - run: npm run -- lerna run test