common.sh: add milliseconds to timestamp

We've started doing this in chromite, so update this too.

BUG=None
TEST=CQ passes

Change-Id: I8bcbe31776862136646626577a56359b19475d05
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3588556
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Sloan Johnson <sloanjohnson@google.com>
Commit-Queue: Sloan Johnson <sloanjohnson@google.com>
1 file changed