update version in readme

Author: jdidion

README.md

@@ -48,7 +48,7 @@ See documentation on [fgpyo.readthedocs.org][rtd-link].
 A simple way to create an environment with the desired version of python and poetry is to use [conda][conda-link].  E.g.:
 
 ```bash
-conda create -n fgpyo -c conda-forge "python>=3.6" poetry
+conda create -n fgpyo -c conda-forge "python>=3.8" poetry
 conda activate fgpyo
 poetry install
 ```