fix(addLabel): update Label type & add some integration test

[evenchange4]

No description provided.

[codecov]

Codecov Report

Merging #10 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #10      +/-   ##
==========================================
+ Coverage   97.56%   97.61%   +0.05%     
==========================================
  Files           6        6              
  Lines          41       42       +1     
  Branches        2        2              
==========================================
+ Hits           40       41       +1     
  Misses          1        1

Impacted Files	Coverage Δ
src/listener.js	94.73% <100%> (+0.29%)	⬆️

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