Allow gopherbot to edit hashtags.

This time with the correct bot group. (CL 108255 was wrong)

Updates golang/go#24836

Change-Id: I1987cc92fa86edee622e39be5e1d01b265e2fc63
Reviewed-on: https://go-review.googlesource.com/108256
Reviewed-by: Andrew Bonventre <andybons@golang.org>