Support nested compressed files

[konstntokas]

Closes #11

[codecov]

Codecov Report

Attention: Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 98.13%. Comparing base (06d2f31) to head (437a7eb).

Files with missing lines	Patch %	Lines
xcube_zenodo/preload.py	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #12      +/-   ##
==========================================
- Coverage   98.53%   98.13%   -0.40%     
==========================================
  Files           7        7              
  Lines         205      215      +10     
==========================================
+ Hits          202      211       +9     
- Misses          3        4       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.