findmissing: use UTC explicitly

The GCE running the robot uses UTC.

When calling get_current_time() from local machines, the time will be
local time.

To be consistent, use UTC explicitly.

BUG=b:271216519
TEST=python3 -c \
	'import time;
	 print(time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime()))'

Change-Id: I57b0e18fe606cf639e70afafb490c91be47c5e02
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/4295338
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Tested-by: Tzung-Bi Shih <tzungbi@chromium.org>
Commit-Queue: Tzung-Bi Shih <tzungbi@chromium.org>
1 file changed