test: Add option to filter out non-cros workon packages.

Add option to filter out non-cros_workon packages from the list of
packages given.

BUG=b:187795989
TEST=./generate

Change-Id: I2f561ca4736d79dc4ea1858f886ee121863b2c6e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2897130
Auto-Submit: Navil Perez <navil@google.com>
Commit-Queue: Sean McAllister <smcallis@google.com>
Reviewed-by: Sean McAllister <smcallis@google.com>
2 files changed