[casviewer] add cas-viewer prod to app.yaml
[casviewer] add cas-viewer prod to app.yaml

Bug: 1114030
Change-Id: I3a3f17f77b434c4fa047093c79672fc267b874b8
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2437533
Auto-Submit: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Commit-Queue: Ye Kuang <1cd89f22f3967fc3dcb883b53940be4b98ec483f@google.com>
Reviewed-by: Ye Kuang <1cd89f22f3967fc3dcb883b53940be4b98ec483f@google.com>
Reviewed-by: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go