[Bug]: deletion of files still not working

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Describe the bug

The fix #551 is actually not fixing the issue for all cases (e.g. if squash commits/merges are used).
With #618 there is an option to get the hash of the last source merge.
With this hash it is possible to get all deleted files from the source from the delta of this hash to the HEAD.

### Expected Behavior

The deletion feature is working as expected

### Current Behavior

If using features like squashing the hash is lost from last merge. In such cases the deletion is not working.

### Steps To Reproduce

_No response_

### Possible Solution

Use the tag from #618

### Additional Information/Context

_No response_

### Template sync version Version

v2