docs(rest-api): specify the date-time format in query string parameters

Author: AndreaGiulianelli

Diff for: docs/rest-api/rest-api-docs.yml

@@ -76,7 +76,7 @@ paths:
         - in: query
           name: dateTime
           required: false
-          description: Specify a past date in order to obtain historical data
+          description: Specify a past date in order to obtain historical data. The date must be specified in the ISO 8601 UTC date format.
           schema:
             type: string
             format: date-time
@@ -153,7 +153,7 @@ paths:
         - in: query
           name: dateTime
           required: false
-          description: Specify a past date in order to obtain historical data
+          description: Specify a past date in order to obtain historical data. The date must be specified in the ISO 8601 UTC date format.
           schema:
             type: string
             format: date-time