restore docs workflow

Author: schl3ck

.github/workflows/docs.yaml

@@ -0,0 +1,28 @@
+name: Node.js CI
+
+on:
+  push:
+    branches: [master]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js
+        uses: actions/setup-node@v1
+        with:
+          node-version: '12.x'
+      - name: Install dependencies
+        run: npm install
+      - name: Build docs
+        run: npm run docs
+      - name: Deploy to GitHub Pages
+        if: success()
+        uses: crazy-max/ghaction-github-pages@v2
+        with:
+          target_branch: gh-pages
+          build_dir: docs
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}