dev: Remove unused copyright2022.txt file

BUG=none
TEST=cq

Change-Id: Ic7258f7d92668343521d4de6f0e15e52ac0873dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/6261412
Commit-Queue: Derek Beckett <dbeckett@chromium.org>
Auto-Submit: Jae Hoon Kim <kimjae@chromium.org>
Tested-by: Jae Hoon Kim <kimjae@chromium.org>
Reviewed-by: Derek Beckett <dbeckett@chromium.org>
1 file changed