proto: update analytics proto for suite scheduler

- Remove new build trigger. Timely triggered jobs also use branch spec
  to filter the target build. Move it to BuildFilters.
- Create a IntervalTrigger to hold the suite running on new_build.
- Replace firmware_build in MatchedBuild to
  firmware_ro_build/firmware_rw_build.
- Polish the repeated field name to plural form.

BUG=1029994
TEST=NA

Change-Id: Iaef28dc9021b956f07bcd9fcd9f98e4b64f35e97
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2017567
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
Commit-Queue: Xinan Lin <linxinan@chromium.org>
Tested-by: Xinan Lin <linxinan@chromium.org>
3 files changed