chore(deps): update pnpm to v8.15.4

Author: renovate[bot]

package.json

@@ -20,7 +20,7 @@
     "prepare": "ts-patch install -s",
     "release": "bumpp"
   },
-  "packageManager": "pnpm@8.10.2",
+  "packageManager": "pnpm@8.15.4",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/sonofmagic/CSS.unescape.git"