feat: Node.js SDK supports event tracker

[frankzhaopeng]

resolves: FeatureProbe/FeatureProbe#277

[github-actions]

Please adjust your PR title to match the Conventional Commits spec.

For example:

• fix: fix http client code
• feat: allow provided config object to extend other configs
• refactor!: drop support for node 6
• feat(ui): add button component

[codecov-commenter]

Codecov Report

Merging #11 (1b4d127) into main (ff0f2bc) will decrease coverage by 0.61%.
The diff coverage is 50.00%.

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@@            Coverage Diff             @@
##             main      #11      +/-   ##
==========================================
- Coverage   80.47%   79.87%   -0.61%     
==========================================
  Files           6        6              
  Lines         630      641      +11     
  Branches      120      125       +5     
==========================================
+ Hits          507      512       +5     
- Misses        122      128       +6     
  Partials        1        1              

Impacted Files	Coverage Δ
src/FeatureProbe.ts	80.67% <33.33%> (-2.52%)	⬇️
src/Evaluate.ts	78.55% <60.00%> (-0.28%)	⬇️
src/Event.ts	82.85% <100.00%> (ø)