Update a policy

const policy = await privy.updatePolicy({
  id: 'fmfdj6yqly31huorjqzq38zc',
  name: 'Transactions must be <= 5ETH',
  rules: [
    {
      name: 'Transactions must be <= 5ETH',
      method: 'eth_sendTransaction',
      action: 'ALLOW',
      conditions: [
        {
          fieldSource: 'ethereum_transaction',
          field: 'value',
          operator: 'lte',
          value: '5000000000000000000000'
        }
      ]
    }
  ]
});