ci: upgrade Node.js 16 → 20 LTS to fix fantasticon 4.1.0 build failure (#450)

* Initial plan

* fix: upgrade Node.js from 16 to 20 LTS in CI workflows to fix fantasticon 4.1.0 build error

Co-authored-by: rzhao271 <7199958+rzhao271@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: rzhao271 <7199958+rzhao271@users.noreply.github.com>

Author: Copilot

.github/workflows/gh-pages.yml

@@ -27,7 +27,7 @@ jobs:
 
       - uses: actions/setup-node@v4
         with:
-          node-version: '16'
+          node-version: '20'
 
       - name: Install dependencies
         run: npm install

.github/workflows/release.yml

@@ -20,7 +20,7 @@ jobs:
           fetch-depth: 0 # All history
       - uses: actions/setup-node@v4
         with:
-          node-version: '16'
+          node-version: '20'
 
       - name: Install dependencies
         run: npm install