Add site built caching

Author: oeway

.github/workflows/build-site.yml

@@ -14,17 +14,22 @@ jobs:
 
     runs-on: ubuntu-latest
 
-    strategy:
-      matrix:
-        node-version: ["13.14"]
-
     steps:
     - uses: actions/checkout@v2
-    - name: Use Node.js ${{ matrix.node-version }}
+    - name: Use Node.js
       uses: actions/setup-node@v1
       with:
-        node-version: ${{ matrix.node-version }}
-    - run: npm ci
+        node-version: "13.14"
+
+    - name: Cache dependencies
+      uses: actions/cache@v2
+      with:
+        path: ~/.npm
+        key: npm-${{ hashFiles('package-lock.json') }}
+        restore-keys: npm-
+
+    - name: Install dependencies
+      run: npm ci --ignore-scripts
     - run: npm run check-format
     - run: npm run build
     - name: Save build output