Adds support for listing inventory. This closes #46

[codecov[bot]]

Codecov Report

Merging #51 (2cfc72a) into main (9ac0b3f) will increase coverage by 2.20%. Report is 1 commits behind head on main. The diff coverage is 75.00%.

@@            Coverage Diff             @@
##             main      #51      +/-   ##
==========================================
+ Coverage   43.12%   45.32%   +2.20%     
==========================================
  Files           8        8              
  Lines         269      289      +20     
==========================================
+ Hits          116      131      +15     
- Misses        135      139       +4     
- Partials       18       19       +1     

Files Changed	Coverage Δ
testdiscogs.go	0.00% <0.00%> (ø)
marketplace.go	74.54% <83.33%> (+4.27%)	:arrow_up: