Version is missing in Markdown .info.yml file and since Editor is dependent on version which should be at least 2.x, you get an error:

Editor.md requires this module and version. Currently using Markdown version (Currently using Unresolved dependency Markdown (Version >=8.x-2.x required))

This happens because drush does not recognize Markdown version which can be seen with: drush pm-list --type=module --no-core

Comments

Vladimir Tanovic created an issue. See original summary.

markhalliwell’s picture

markhalliwell
Primary language English
commented
Status: Active » Closed (works as designed)

That's because versions are only added during the packing process on d.o.

If you download https://ftp.drupal.org/files/projects/markdown-8.x-2.x-dev.tar.gz, you'll see:

# Information added by Drupal.org packaging script on 2019-10-12
version: '8.x-2.0-alpha1+16-dev'
project: 'markdown'
datestamp: 1570922584

I suspect you're using composer to install your requirements, you should use --prefer-dist when installing or updating as this will use the packaged tarballs rather than cloning the project's repo (which doesn't have the version).