Fix GitHub Actions: Update Node.js version to 20 for Vite legacy plugin compatibility

Author: robertpitt

.github/workflows/deploy.yml

@@ -14,11 +14,11 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Setup Node.js
-        uses: actions/setup-node@v4
-        with:
-          node-version: "18"
-          cache: "yarn"
+       - name: Setup Node.js
+         uses: actions/setup-node@v4
+         with:
+           node-version: "20"
+           cache: "yarn"
 
       - name: Install dependencies
         run: yarn install --frozen-lockfile