Update dependency react-email to v6

Author: renovate[bot]

package.json

@@ -15,7 +15,7 @@
     "@react-email/preview-server": "5.0.5",
     "@types/react": "^19.0.1",
     "@types/react-dom": "^19.0.1",
-    "react-email": "5.0.5",
+    "react-email": "6.0.0",
     "typescript": "^5.9.3"
   }
 }