Exclude the issue owner's own comment from first response

[eichisanden]

I think the comments of the owner of the issue themselves should be excluded from Time to first response.

Because they will add something that they forgot to write in the body of the Issue, or make additional comments to supplement the body of the Issue(like #26).

We could modify it as the default behavior, but if we are more cautious, we might add an option like IGNORE_OWNER_COMMENT.

[zkoppert]

I think that changing default behavior is okay in this case. Great catch on this situation. I normally modify my issue descriptions rather than comment to add more information so I wouldn't have thought of this one. I'm sure lots of people comment like described.