Update noaa-gsod.yaml (awslabs#1030)

Change to update frequency text

Author: Patrick-Keown

datasets/noaa-gsod.yaml

@@ -20,7 +20,7 @@ ManagedBy: "[NOAA](http://www.noaa.gov/)"
 Contact: |
   For any questions regarding data delivery not associated with this platform or any general questions regarding the NOAA Big Data Program, email noaa.bdp@noaa.gov.
   <br /> We also seek to identify case studies on how NOAA data is being used and will be featuring those stories in joint publications and in upcoming events. If you are interested in seeing your story highlighted, please share it with the NOAA BDP team here: noaa.bdp@noaa.gov
-UpdateFrequency: Currently updated infrequently. Last updated on September 13, 2016.
+UpdateFrequency: Data is updated as new products are available.
 Collabs:
   ASDI:
     Tags: