update readme and setup

README.md

@@ -4,7 +4,7 @@ Fluvial Egg Drift Simulator
 
 ## Suggested citation
 
-Domanski, M.M., 2019, FluEgg, U.S. Geological Survey software release, https://doi.org/10.5066/P93UCQR2.
+Domanski, M.M., Berutti, M.C., 2020, FluEgg, U.S. Geological Survey software release, https://doi.org/10.5066/P93UCQR2.
 
 ## References
 

setup.py

@@ -48,7 +48,7 @@ setup_kwargs = {
     ],
     'long_description': long_description,
     'long_description_content_type': 'text/markdown',
-    'python_requires': '>=3.6',
+    'python_requires': '>=3.7',
     'install_requires': install_requirements,
 }