Remove shortLabel from required output

[cmdcolin]

This would be part of fixing #18

Can be paired with https://github.com/GMOD/jbrowse-components/tree/allow_encodeproject_trackhub as an example

[codecov]

Codecov Report

Merging #23 (6b3d480) into master (1d59343) will decrease coverage by 0.45%.
Report is 13 commits behind head on master.
The diff coverage is 100.00%.

❗ Current head 6b3d480 differs from pull request most recent head f7f285b. Consider uploading reports for the commit f7f285b to get more accurate results

@@            Coverage Diff             @@
##           master      #23      +/-   ##
==========================================
- Coverage   96.03%   95.59%   -0.45%     
==========================================
  Files           7        7              
  Lines         227      227              
  Branches       62       62              
==========================================
- Hits          218      217       -1     
- Misses          8        9       +1     
  Partials        1        1              

Files	Coverage Δ
src/trackDbFile.js	97.87% <100.00%> (-2.13%)	⬇️

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[cmdcolin]

refreshed to be up to date