Add sequence steps

curl --request POST \
  --url https://stoplight.io/mocks/replyteam/reply/765516802/sequences/{id}/steps \
  --header 'Content-Type: application/json' \
  --data '[
  {
    "id": 123,
    "type": "Email",
    "number": 1,
    "delayInMinutes": 0,
    "template": {
      "id": 456,
      "subject": "Introduction Email",
      "body": "Hi {{firstName}},\n\nI wanted to reach out regarding..."
    }
  }
]'

[
  {
    "id": 123,
    "type": "Email",
    "number": 1,
    "delayInMinutes": 0,
    "template": {
      "id": 456,
      "subject": "Introduction Email",
      "body": "Hi {{firstName}},\n\nI wanted to reach out regarding..."
    }
  }
]