Add Cookie to KeyAuth middleware's KeyLookup

[rohitkg98]

Closes #1885

[codecov]

Codecov Report

Merging #1929 (edfd55b) into master (58366f9) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1929      +/-   ##
==========================================
+ Coverage   90.97%   90.99%   +0.02%     
==========================================
  Files          32       32              
  Lines        2792     2799       +7     
==========================================
+ Hits         2540     2547       +7     
  Misses        161      161              
  Partials       91       91              

Impacted Files	Coverage Δ
middleware/key_auth.go	96.92% <100.00%> (+0.37%)	⬆️

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[vishr]

@all-contributors please add @aldas for review

[allcontributors]

@vishr

I've put up a pull request to add @aldas! 🎉