Add Actinia Grass GIS (#2640)

README.md

@@ -772,6 +772,7 @@ API | Description | Auth | HTTPS | CORS |
 API | Description | Auth | HTTPS | CORS |
 |---|---|---|---|---|
 | [Abstract IP Geolocation](https://www.abstractapi.com/ip-geolocation-api) | Geolocate website visitors from their IPs | `apiKey` | Yes | Yes |
+| [Actinia Grass GIS](https://actinia.mundialis.de/api_docs/) | Actinia is an open source REST API for geographical data that uses GRASS GIS | `apiKey` | Yes | Unknown | 
 | [adresse.data.gouv.fr](https://adresse.data.gouv.fr) | Address database of France, geocoding and reverse | No | Yes | Unknown |
 | [Airtel IP](https://sys.airtel.lv/ip2country/1.1.1.1/?full=true) | IP Geolocation API. Collecting data from multiple sources | No | Yes | Unknown |
 | [apilayer ipstack](https://ipstack.com/) | Locate and identify website visitors by IP address | `apiKey` | Yes | Unknown |