fix: use constant for path separator

[scolladon]

Explain your changes

---

Use constant for path separator

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (e6d6e34) 100.00% compared to head (7401a12) 99.80%.

❗ Current head 7401a12 differs from pull request most recent head 8765c84. Consider uploading reports for the commit 8765c84 to get more accurate results

Files	Patch %	Lines
src/utils/fsHelper.ts	50.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              main     #766      +/-   ##
===========================================
- Coverage   100.00%   99.80%   -0.20%     
===========================================
  Files           37       37              
  Lines         1040     1049       +9     
  Branches       113      113              
===========================================
+ Hits          1040     1047       +7     
- Misses           0        2       +2     

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[codeclimate]

Code Climate has analyzed commit 7401a12 and detected 0 issues on this pull request.

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[github-actions]

Shipped in release v5.35.1.
You can install the new version using the version number or the latest-rc channel

$ sfdx plugins:install sfdx-git-delta@latest-rc
$ sfdx plugins:install sfdx-git-delta@v5.35.1

Happy incremental deployment!