build: Fix JSR publish for eslint/core (#199)

Author: nzakas

packages/core/package.json

@@ -40,6 +40,7 @@
     "@types/json-schema": "^7.0.15"
   },
   "devDependencies": {
+    "json-schema": "^0.4.0",
     "typescript": "^5.8.3"
   },
   "engines": {