godash: fix link to 'about the dashboard'
godash: fix link to 'about the dashboard'

Change-Id: I3fe1fdfc28b1d7503e96b4c8561ecd8bf177c89f
Reviewed-on: https://go-review.googlesource.com/23381
Reviewed-by: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

golang/build,golang/build,golang/build,golang/build