chore: fix typo in docs

docs/molgenis/use_schema.md

@@ -100,7 +100,7 @@ When uploading csv/excel all empty cells will receive the defaultValue (in inser
 Optionally you can also use javascript expressions. For example:
 * ```duck``` would set a string value
 * ```1``` would set a numeric value
-* ```=new Date().toJSONString()``` provides automatic date/dateTime
+* ```=new Date().toISOString()``` provides automatic date/dateTime
 * ```={name:"green"}``` could be default value for an ontology_
 * ```=[{name:"green"}]``` could be default value for an ontology_array