docs: fix node version in CONTRIBUTING.md

[exoego]

📑 Summary

Resolves #5572

📏 Design Decisions

N/A

📋 Tasks

Make sure you

• 📖 have read the contribution guidelines
• 💻 have added necessary unit/e2e tests.
• 📓 have added documentation. Make sure MERMAID_RELEASE_VERSION is used for all new features.
• 🔖 targeted develop branch

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 5.73%. Comparing base (63f9e95) to head (9c3bcec).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #5573   +/-   ##
=======================================
  Coverage     5.73%   5.73%           
=======================================
  Files          277     277           
  Lines        41988   41988           
  Branches       515     515           
=======================================
  Hits          2409    2409           
  Misses       39579   39579           

Flag	Coverage Δ
unit	5.73% <ø> (ø)

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[nirname]

Thank you for the contribution. I know it is a bit confusing, but no need for updating docs folder manually (only those which are inside the package).

[mermaid-bot]

@exoego, Thank you for the contribution!
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