update license

LICENSE.md

@@ -5,7 +5,7 @@ Unless otherwise noted, This project is in the public domain in the United
 States because it contains materials that originally came from the United
 States Geological Survey, an agency of the United States Department of
 Interior. For more information, see the official USGS copyright policy at
-https://www2.usgs.gov/visual-id/credit_usgs.html#copyright
+https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits
 
 Additionally, we waive copyright and related rights in the work
 worldwide through the CC0 1.0 Universal public domain dedication.
@@ -40,7 +40,3 @@ this deed makes no warranties about the work, and disclaims liability for
 all uses of the work, to the fullest extent permitted by applicable law.
 When using or citing the work, you should not imply endorsement by the
 author or the affirmer.
-
-
-
-[1]: https://creativecommons.org/publicdomain/zero/1.0/legalcode
\ No newline at end of file