Another attempt at fixing #2. b216057 had a bug where you couldn't pass
a file through stdin because we tried to read the file twice, which we
can't do if the input is a pipe.
Fix `autotag` so you can pass a filename of '-' to read a file from
stdin. This way you can do this:
docker run --rm -i ghcr.io/danbooru/autotagger autotag - < image.jpg
...to perform prediction on a single file outside of Docker.
evazion