Add Kathryn Materna to AUTHORS.md (#1007)

Author: kmaterna

AUTHORS.md

@@ -10,6 +10,7 @@ The following people have contributed code and/or documentation to the project
 
 * [Dongdong Tian](https://seisman.info/) | [0000-0001-7967-1197](https://orcid.org/0000-0001-7967-1197) | Michigan State University
 * [Jiayuan Yao](https://github.com/core-man) | [0000-0001-7036-4238](https://orcid.org/0000-0001-7036-4238) | Nanyang Technological University
+* [Kathryn Materna](https://github.com/kmaterna) | [0000-0002-6687-980X](https://orcid.org/0000-0002-6687-980X) | US Geological Survey
 * [Leonardo Uieda](http://www.leouieda.com/) | [0000-0001-6123-9515](https://orcid.org/0000-0001-6123-9515) | University of Liverpool
 * [Liam Toney](https://liam.earth/) | [0000-0003-0167-9433](https://orcid.org/0000-0003-0167-9433) | University of Alaska Fairbanks
 * [Malte Ziebarth](https://github.com/mjziebarth) | [0000-0002-5190-4478](https://orcid.org/0000-0002-5190-4478) | GFZ German Research Centre for Geosciences