todo: list of subdirs

[Ana Trisovic]

[Ana Trisovic]

Tests:

• works locally
• works with

GITHUB_DIRS: |
              dir1
              dir2
              dir3

• works with GITHUB_DIR: dir1 dir2 dir3
• works with GITHUB_DIR: dir1
• works with GITHUB_DIR: dir1,dir2,dir3

See the commit history of: https://github.com/atrisovic/joss-reviews