fix: upgrade prettier-plugin-package to v2 for prettier 3 compat

prettier-plugin-package v1.x requires prettier ^2, which conflicts
with our upgrade to prettier ^3.7.1. v2.0.0 supports prettier ^3.

Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: bennypowers

package-lock.json

@@ -72,7 +72,7 @@
     "mocha": "^10.8.2",
     "nanocolors": "^0.2.1",
     "prettier": "^3.7.1",
-    "prettier-plugin-package": "^1.3.0",
+    "prettier-plugin-package": "^2.0.0",
     "rimraf": "^4.4.1",
     "rollup": "^4.4.0",
     "ts-node": "^10.4.0",