dl: add go1.13.7 and go1.12.16

Change-Id: I4535827d11e4eccb3634af3e0739002d9bc5f423
Reviewed-on: https://go-review.googlesource.com/c/dl/+/216679
Run-TryBot: Katie Hockman <katie@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2 files changed