fix pnpm not being found

Author: jwangkun

.github/workflows/release.yml

@@ -20,6 +20,10 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '20'
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 9
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
       - name: Type check