Adding SwiftKanban API under Business category (public-apis#1516)

It is similar to Trello but much more powerful and feature-rich.

README.md

@@ -152,6 +152,8 @@ API | Description | Auth | HTTPS | CORS |
 | [MailboxValidator](https://www.mailboxvalidator.com/api-email-free) | Validate email address to improve deliverability | `apiKey` | Yes | Unknown |
 | [mailgun](https://www.mailgun.com/) | Email Service | `apiKey` | Yes | Unknown |
 | [markerapi](http://www.markerapi.com/) | Trademark Search | No | No | Unknown |
+| [SwiftKanban](https://www.digite.com/swiftkanban/) | Kanban software, Visualize Work, Increase Organizations Lead Time, Throughput & Productivity | `apiKey` | Yes | Unknown |
+| [Ticksel](https://ticksel.com) | Friendly website analytics made for humans | No | Yes | Unknown |
 | [Trello](https://developers.trello.com/) | Boards, lists and cards to help you organize and prioritize your projects | `OAuth` | Yes | Unknown |
 
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