Add Salesfly PDF API (#1289)

README.md

@@ -349,6 +349,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Pocket](https://getpocket.com/developer/) | Bookmarking service | `OAuth` | Yes | Unknown |
 | [PrexView](https://prexview.com) | Data from XML or JSON to PDF, HTML or Image | `apiKey` | Yes | Unknown |
 | [Restpack](https://restpack.io/) | Provides screenshot, HTML to PDF and content extraction APIs | `apiKey` | Yes | Unknown |
+| [Salesfly PDF](https://salesflypdf.com) | HTML/URL to PDF | `apiKey` | Yes | Yes |
 | [Todoist](https://developer.todoist.com) | Todo Lists | `OAuth` | Yes | Unknown |
 | [Vector Express v2.0](https://vector.express) | Free vector file converting API | No | Yes | No |
 | [WakaTime](https://wakatime.com/developers) | Automated time tracking leaderboards for programmers | No | Yes | Unknown |