Fix .gitignore search in FileWatcher

[LaryStef]

Summary

When using --reload-dir, the FileWatcher can't find .gitignore file since it only looks in the watched directory, not in the project root.

Changes

• FileWatcher now start searching for .gitignore in --reload-dir directory and goes upper until it reaches project root.

Fixes #591 issue.
I suppose it was broken first time here.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.45%. Comparing base (f6c96b2) to head (13dc1af).
⚠️ Report is 80 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #598      +/-   ##
==========================================
+ Coverage   77.70%   78.45%   +0.74%     
==========================================
  Files          62       68       +6     
  Lines        1933     2413     +480     
==========================================
+ Hits         1502     1893     +391     
- Misses        431      520      +89     

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