Runs odt2txt with invalid options

Running diffoscope on two odt files reports:

│┄ Command `'odt2txt --stdout {}'` failed with exit code 1. Standard output:
│┄     odt2txt 0.5
│┄     […]

It seems this is because odt2txt doesn't support a --stdout option. The man page seems to imply that output goes to stdout by default:

          --output=file Write output to file, instead of STDOUT

I'm running debian unstable, with package versions:

ii  diffoscope     198          all          in-depth visual diff tool for files, archives and directories
ii  odt2txt        0.5-7        amd64        simple converter from OpenDocument Text to plain text