update readme to reflect changes

Author: Stian Larsen

README.md

@@ -32,7 +32,7 @@ docker create \
 * `--net=host` - Shares host networking with container, **required**.
 * `-v /config` - Plex library location. *This can grow very large, 50gb+ is likely for a large collection.*
 * `-v /data/xyz` - Media goes here. Add as many as needed e.g. `/data/movies`, `/data/tv`, etc.
-* `-e VERSION=latest` - Permits specific version selection e.g. `0.9.12.4.1192-9a47d21`, also supports `latest`. If left blank, auto update is disabled until set.
+* `-e VERSION=latest` - Permits specific version selection e.g. `0.9.12.4.1192-9a47d21`, also supports `public` (this forces plex so stick with ). If left blank, auto update is disabled until set.
 * `-e PGID=` for for GroupID - see below for explanation
 * `-e PUID=` for for UserID - see below for explanation