fix: support more than one invoke at same time

[echosoar]

No description provided.

[codecov-io]

Codecov Report

Merging #89 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #89      +/-   ##
==========================================
+ Coverage   80.66%   80.67%   +<.01%     
==========================================
  Files          72       72              
  Lines        2560     2561       +1     
  Branches      239      239              
==========================================
+ Hits         2065     2066       +1     
  Misses        493      493              
  Partials        2        2

Impacted Files	Coverage Δ
packages/serverless-invoke/src/core.ts	78.57% <100%> (+0.19%)	⬆️

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