Support ignoring file deletions

[johnlk]

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update

Description

This change supports ignoring files which are wholly deleted. This seems to be a common ask. The new config variable is called ignore_file_deletions and relies on the files API to determine the status of a file.

This change was inspired by #61 , but with updated patterns and tests.

How to test

I added unit tests for the new code paths to ensure everything is behaving as expected.

Link to issues addressed

• ISSUE-66

[johnlk]

cc: @OnkarRuikar

[JavierCane]

Hi @johnlk, gooooooood work 🎉 🙌

1. I have taken the freedom to commit some README.md changes in the branch instead of making them as a PR comment suggestions because GitHub does not allow me to do so due to implying some non-modified lines 😬

   Feel free to discuss any concern regarding the changes 🙏😇

2. Regarding the inspiration on Implementation for ignore_deleted option #61, I completely understand that, given the modifications in the project since that PR it is easier to implement it in a new PR (my fault on not reviewing them on time). However, I would propose to add @rwyland
   as the merge commit co-author in order to give him credit for the contribution 😊

   Taking a look to his contributions to other public repositories, it would be just by adding the following to the merge commit:

   
   Co-authored-by: Rob W <rlw0788@gmail.com>