chore: update Node.js and pnpm setup in OpenAPI sync workflow

- Upgraded the pnpm action to version 4 for improved performance.
- Specified Node.js version to 20.16.0 and enabled caching for pnpm to optimize dependency installation.

.github/workflows/sync-openapi-docs.yml

@@ -21,16 +21,11 @@ jobs:
         uses: actions/checkout@v4
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Setup Node.js
-        uses: actions/setup-node@v4
+      - uses: pnpm/action-setup@v4
+      - uses: actions/setup-node@v4
         with:
-          node-version: '20'
-
-      - name: Setup pnpm
-        uses: pnpm/action-setup@v2
-        with:
-          version: 8
+          node-version: 20.16.0
+          cache: "pnpm"
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile