`None` if `self.is_pull_request` is `False`.
`True` if there are conflicting files but the list can't be retrieved.
target_branch (`str`, *optional*):
The branch into which changes are to be merged if this is a
Pull Request . `None`  if `self.is_pull_request` is `False`.
merge_commit_oid (`str`, *optional*):
If this is a merged Pull Request , this is set to the OID / SHA of
the merge commit, `None` otherwise.
diff (`str`, *optional*):
The git diff if this is a Pull Request , `None` otherwise.