fix: use finishModules if thread is less than or equal 1

[ricardogobbosouza]

Resolve #83

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• typo fix
• metadata update

[codecov]

Codecov Report

Merging #95 (9922b6b) into master (6fc6874) will decrease coverage by 0.39%.
The diff coverage is 80.00%.

@@             Coverage Diff             @@
##            master      #95      +/-   ##
===========================================
- Coverage   100.00%   99.60%   -0.40%     
===========================================
  Files            8        8              
  Lines          253      255       +2     
  Branches        72       73       +1     
===========================================
+ Hits           253      254       +1     
- Misses           0        1       +1     

Impacted Files	Coverage Δ
src/index.js	98.46% <75.00%> (-1.54%)	⬇️
src/linter.js	100.00% <100.00%> (ø)

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[alexander-akait]

/cc @jsg2021 Can you test locally?

[jsg2021]

This does appear to resolve the threading performance regression :)