update licence

LICENSE

@@ -4,13 +4,13 @@
 |-----------------|----------------------------|-------------------------------------------|
 | `trajectories/` | OpenSky Network (Trino)    | OpenSky Network Data License Agreement — non-profit research/education only. Redistributed with written permission of the OpenSky Network. |
 | `splits/`       | Own work                   | CC BY 4.0                                 |
-| `terrain/`      | Copernicus DEM GLO-30      | Licence for the use of the Copernicus WorldDEM-30 |
+| `terrain/`      | Copernicus DEM GLO-90, retrieved via the Copernicus Data Space Ecosystem Sentinel Hub Process API (`demInstance: COPERNICUS_90`) | Licence for the use of the Copernicus WorldDEM-90 |
 | `runways/`      | X-Plane Scenery Gateway    | GNU GPL v2                                |
 | `osm/`          | OpenStreetMap contributors | ODbL 1.0                                  |
-| `procedures/`   | AIRAC API (airac.net)      | Redistributed with permission of airac.net; no open license. |
+| `procedures/`   | AIRAC API (airac.net)      | no license listed. |
 
 ## Required notices
 - Cite: Schäfer et al., "Bringing up OpenSky: A large-scale ADS-B sensor network for research", IPSN 2014.
-- Produced using Copernicus WorldDEM-30 © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved.
+- Produced using Copernicus WorldDEM-90 © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved.
 - The organisations in charge of the Copernicus programme by law or by delegation do not incur any liability for any use of the Copernicus WorldDEM-30.
 - © OpenStreetMap contributors, available under the Open Database License (ODbL).