feat: add --no-mirror option

[guedou]

Context

Cloning a repository with git clone --mirror may retrieve more git objects, and lead to more secrets being detected.

What has been done

By default ggshield now used --mirror. A new command line option could be used to disable this feature.

Validation

Clone https://github.com/nightwatchcybersecurity/gb_testrepo_delete?tab=readme-ov-filewith and without the new option.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.90%. Comparing base (537dbb8) to head (b0a6765).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #981   +/-   ##
=======================================
  Coverage   91.90%   91.90%           
=======================================
  Files         181      181           
  Lines        7593     7593           
=======================================
  Hits         6978     6978           
  Misses        615      615           

Flag	Coverage Δ
unittests	91.90% <ø> (ø)

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[agateau-gg]

Hi, sorry for the late review. This looks good! It's always nice to be able to spot more secrets!

I think we don't need the --no-mirror option. I'd rather not have it for now and add it only if we find a use-case for it: That's one less code path to test.

[agateau-gg]

Looks good, thanks!