fix(serve): signal group couldn't be canceled

[Reasno]

No description provided.

[codecov]

Codecov Report

Merging #208 (38178a8) into master (e72a19d) will decrease coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #208      +/-   ##
==========================================
- Coverage   82.17%   82.13%   -0.05%     
==========================================
  Files          90       90              
  Lines        3451     3453       +2     
==========================================
  Hits         2836     2836              
- Misses        460      461       +1     
- Partials      155      156       +1     

Impacted Files	Coverage Δ
serve.go	90.51% <100.00%> (+0.16%)	⬆️
config/watcher/file.go	58.13% <0.00%> (-4.66%)	⬇️

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