Deepen shallow clones before running diff

[shiroyasha]

If the cloned repository is not deep enough (cloned with --depth N), the change_in evaluation fails.

In this PR, we are introducing a procedure for an iterative deepening of the git history until change_in is ready to be resolved.

Demonstrative pseudocode:

while gitDiffIsFailing? do
  run "git fetch --deepen 100"
end

We are running with an iterative approach instead of a full clone in order to better support large git repositories. For example, a full git clone can be 80gb, but the relevant parts (the last N commits) might be much lighter.

The iterative deepening will halt with an error at 10,000 commits. This should be enough for most, if not all use cases.

When this change is introduced, the output of the CLI will be:

[shiroyasha]

Update:

• removed the unnecessary string() conversions.
• Introduced exponential deepening, 100, 200, 400, ... commits.

cc @DamjanBecirovic