sponsorship tier_changed event

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "#/components/schemas/webhook-sponsorship-tier-changed",
  "title": "sponsorship tier_changed event",
  "type": "object",
  "properties": {
    "action": {
      "type": "string",
      "enum": [
        "tier_changed"
      ]
    },
    "changes": {
      "$ref": "#/components/schemas/webhooks_changes_8"
    },
    "enterprise": {
      "$ref": "#/components/schemas/enterprise-webhooks"
    },
    "installation": {
      "$ref": "#/components/schemas/simple-installation"
    },
    "organization": {
      "$ref": "#/components/schemas/organization-simple-webhooks"
    },
    "repository": {
      "$ref": "#/components/schemas/repository-webhooks"
    },
    "sender": {
      "$ref": "#/components/schemas/simple-user-webhooks"
    },
    "sponsorship": {
      "$ref": "#/components/schemas/webhooks_sponsorship"
    }
  },
  "required": [
    "action",
    "changes",
    "sponsorship",
    "sender"
  ]
}