Remove Yummly

API has been ceased :(

README.md

@@ -343,7 +343,6 @@ API | Description | Auth | HTTPS | CORS |
 | [TheCocktailDB](https://www.thecocktaildb.com/api.php) | Cocktail Recipes | `apiKey` | Yes | Yes |
 | [TheMealDB](https://www.themealdb.com/api.php) | Meal Recipes | `apiKey` | Yes | Yes |
 | [What's on the menu?](http://nypl.github.io/menus-api/) | NYPL human-transcribed historical menu collection | `apiKey` | No | Unknown |
-| [Yummly](https://developer.yummly.com/) | Find food recipes | `apiKey` | Yes | Unknown |
 | [Zomato](https://developers.zomato.com/api) | Discover restaurants | `apiKey` | Yes | Unknown |