zenodo: add description and note

.zenodo.json

@@ -1,10 +1,12 @@
 {
     "title": "EUREC4A",
+    "description": "The catalog describing the <a href=\"https://eurec4a.eu/\">EUREC4A</a> dataset.",
     "communities": [
         {"identifier": "eurec4a"}
     ],
     "access_right": "open",
     "license": "cc-zero",
+    "notes": "The license (CC-0) applies to the dataset <b>catalog</b>. The individual datasets may be subject to different terms. When using the underlying data in publications, please give credit to the individual dataset creators and adhere to the <a href=\"https://eurec4a.eu/data-simulations/data\">EUREC4A data policy</a>.",
     "upload_type": "dataset",
     "creators": [
         {