chore: remove engines field

Author: imtaotao

package.json

@@ -65,9 +65,6 @@
     "url": "https://github.com/imtaotao/danmu/issues"
   },
   "packageManager": "pnpm@9.1.3",
-  "engines": {
-    "node": "^20"
-  },
   "devDependencies": {
     "@jsdevtools/version-bump-prompt": "^6.1.0",
     "@rollup/plugin-commonjs": "^26.0.1",