Updating actions to be compatible with Node.js 24 (#120)

## Description

No Node.js 20 actions, which is deprecated and becomes non-default on
GitHub runners starting June 2, 2026.

Author: retyui

website/src/docs/guides/ci-cd.md

@@ -97,21 +97,21 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install pnpm
-        uses: pnpm/action-setup@v2
+        uses: pnpm/action-setup@v6
         with:
           version: latest
 
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '23'
+          node-version: '24'
           cache: 'pnpm'
 
       - name: Install dependencies
         run: pnpm install
 
       - name: Set up JDK 17
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           java-version: '17'
           distribution: 'temurin'
@@ -161,14 +161,14 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install pnpm
-        uses: pnpm/action-setup@v2
+        uses: pnpm/action-setup@v6
         with:
           version: latest
 
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '18'
+          node-version: '24'
           cache: 'pnpm'
 
       - name: Install Watchman