Update pnpm/action-setup action to v4

Author: renovate[bot]

.github/workflows/lighthouse.yml

@@ -13,7 +13,7 @@ jobs:
           node-version: '22'
 
       - name: Setup pnpm
-        uses: pnpm/action-setup@v2
+        uses: pnpm/action-setup@v4
         with:
           version: 8
           run_install: false