add Datadog API to SIEM section (#48)

Co-authored-by: MJ Anderson <[email protected]>

Author: MJ-ANDERS0N

README.md

@@ -112,6 +112,7 @@ API | Description | Auth | HTTPS | Link | Free / Commercial|
 |---|---|---|---|---|---|
 | ArcSight | HP ArcSight API | `None` | `No` | [Link!](https://h41382.www4.hpe.com/gfs-shared/downloads-273.pdf) | Commercial |
 | AlienVault | AlienVault API | `Yes` | `Yes` | [Link!](https://www.alienvault.com/documentation/api/av-apis.htm) | Commercial |
+| Datadog | Datadog API | `Yes` | `Yes` | [Link](https://docs.datadoghq.com/api/latest/) | Commercial |
 | ELK | ELK Stack API | `None` | `No` | [Link!](https://www.elastic.co/guide/en/elasticsearch/reference/current/docs.html) | OpenSource |
 | Gravwell | Gravwell API | `Yes` | `Yes` | [Link!](https://dev.gravwell.io/docs/#!api/api.md) | Community / Commercial |
 | Humio | Humio API | `Yes` | `Yes` | [Link!](https://docs.humio.com/api/)| Community / Commercial |