Removed Calendar Index (acquired by Calendarific)

Removed Calendar Index to reflect 2018 acquisition by Calendarific. Calendar Index now redirects to Calendarific, and Calendarific is already listed separately, so Calendar Index has been removed.

README.md

@@ -294,7 +294,6 @@ API | Description | Auth | HTTPS | CORS |
 API | Description | Auth | HTTPS | CORS |
 |---|---|---|---|---|
 | [Abstract Public Holidays](https://www.abstractapi.com/holidays-api) | Data on national, regional, and religious holidays via API | `apiKey` | Yes | Yes |
-| [Calendar Index](https://www.calendarindex.com/) | Worldwide Holidays and Working Days | `apiKey` | Yes | Yes |
 | [Calendarific](https://calendarific.com/) | Worldwide Holidays | `apiKey` | Yes | Unknown |
 | [Church Calendar](http://calapi.inadiutorium.cz/) | Catholic liturgical calendar | No | No | Unknown |
 | [Czech Namedays Calendar](https://svatky.adresa.info) | Lookup for a name and returns nameday date | No | No | Unknown |