chore(deps): update actions/setup-node action to v6

Author: renovate[bot]

.github/actions/prepare/action.yml

@@ -7,7 +7,7 @@ runs:
     - uses: pnpm/action-setup@v4.2.0
       with:
         version: 10.20.0
-    - uses: actions/setup-node@v4.4.0
+    - uses: actions/setup-node@v6.0.0
       with:
         node-version: '22.21.1'
         cache: pnpm