Remove old option from readme

README.md

@@ -84,7 +84,6 @@ set -g theme_display_k8s_context yes
 set -g theme_display_hg yes
 set -g theme_display_virtualenv no
 set -g theme_display_virtualenv verbose
-set -g theme_hide_python_version yes
 set -g theme_display_nix no
 set -g theme_display_ruby no
 set -g theme_display_node yes