enhancementgood first issuehacktoberfesthelp wanted
描述
We should filter/convert the line endings in postBuild as that seems to cause problems (see https://github.com/jupyter/repo2docker/issues/237#issuecomment-373446647)
Is there a docker option to have it convert line endings on COPY or do we have to convert it before copying or add a tool like dos2unix to the container?