Fix HUGO CI

Author: tolyo

.github/workflows/gh-pages.yml

@@ -1,11 +1,3 @@
-name: GitHub Pages
-
-on:
-  push:
-    branches:
-      - master
-  pull_request:
-
 jobs:
   deploy:
     runs-on: ubuntu-22.04
@@ -26,6 +18,13 @@ jobs:
         with:
           node-version: lts/*
 
+      - name: Cache npm dependencies
+        uses: actions/cache@v4
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-npm-${{ hashFiles('package-lock.json') }}
+          restore-keys: ${{ runner.os }}-npm-
+
       - name: Install npm dependencies (PostCSS etc.)
         run: npm ci