Update repository review instructions

curl --request PATCH \
  --url https://api.ghostsecurity.ai/v1/repos/{id}/instructions/review \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "enabled": true,
  "instructions": "<string>"
}'

{
  "created_at": "2025-05-29T22:27:39.047356Z",
  "enabled": true,
  "instructions": "Focus on security vulnerabilities and follow OWASP guidelines.",
  "updated_at": "2025-05-29T22:27:39.047356Z"
}