Add AdoptAPet (#2713)

README.md

@@ -108,6 +108,7 @@
 ### Animals
 API | Description | Auth | HTTPS | CORS |
 |---|---|---|---|---|
+| [AdoptAPet](https://www.adoptapet.com/public/apis/pet_list.html) | Resource to help get pets adopted | `apiKey` | Yes | Yes |
 | [Axolotl](https://theaxolotlapi.netlify.app/) | Collection of axolotl pictures and facts | No | Yes | Yes |
 | [Cat Facts](https://alexwohlbruck.github.io/cat-facts/) | Daily cat facts | No | Yes | No |
 | [Cataas](https://cataas.com/) | Cat as a service (cats pictures and gifs) | No | Yes | No |