chore(deps): update pnpm to v9.15.4

Author: renovate[bot]

package.json

@@ -41,5 +41,5 @@
     "vuepress-shared": "2.0.0-rc.38",
     "vuepress-theme-hope": "2.0.0-rc.38"
   },
-  "packageManager": "pnpm@9.5.0"
+  "packageManager": "pnpm@9.15.4"
 }