Commits the current patch. You must have resolved any conflicts that
were introduced during the patch application from the git_rebase_next
invocation.
The author of the updated commit, or NULL to keep the author from the original commit
The encoding for the message in the commit, represented with a standard encoding name. If message is NULL, this should also be NULL, and the encoding from the original commit will be maintained. If message is specified, this may be NULL to indicate that "UTF-8" is to be used.
The message for this commit, or NULL to use the message from the original commit.
Zero on success, GIT_EUNMERGED if there are unmerged changes in the index, GIT_EAPPLIED if the current commit has already been applied to the upstream and there is nothing to commit, -1 on failure.