Add packageManager

Author: mkszepp

package.json

@@ -43,6 +43,7 @@
     "npm": false
   },
   "version": "8.6.0",
+  "packageManager": "pnpm@9.15.9",
   "devDependencies": {
     "@glint/core": "^1.5.0",
     "@release-it-plugins/lerna-changelog": "^7.0.0",