Update node checks

.github/workflows/node.yml

@@ -0,0 +1,33 @@
+name: Node
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+      - stable*
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    name: node
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up node 
+        uses: actions/setup-node@v2
+        with:
+          node-version: 14
+
+      - name: Set up npm7
+        run: npm i -g npm@7
+
+      - name: Install dependencies & build
+        run: |
+          npm ci
+          npm run build --if-present
+
+      - name: Check webpack build changes
+        run: |
+          bash -c "[[ ! \"`git status --porcelain `\" ]] || ( echo 'Uncommited changes in webpack build' && git status && exit 1 )"