Update narou script

Add "/" in HOST-DIR like "-v /mnt/Kindle/:/mnt/Kindle".  Recent
docker-desktop starts requiring this additional "/".  The behaviors
are below.

 - "-v /mnt/Kindle:/mnt/Kindle": mount host's ext4 /mnt/Kindle to
   container.
 - "-v /mnt/Kindle/:/mnt/Kindle": mount host's drvfs /mnt/Kindle/./ to
   container.

narou.sh

@@ -58,7 +58,7 @@ esac
 docker run $TTY --rm $opt \
     -v /var/run/docker.sock:/var/run/docker.sock \
     -v $data:/opt/narou \
-    -v /mnt/Kindle:/mnt/Kindle \
+    -v /mnt/Kindle/:/mnt/Kindle \
     -e NAROU_UID="$( id -u )" \
     -e NAROU_GID="$( id -g )" \
     -e NAROU_USER="$( id -un )" \