findmissing: pip install with hashes

To be more secure, specify the hashes of packages for pip install.

BUG=b:316142484
BUG=b:304262148
TEST=python3 -m venv tmp && source tmp/bin/activate &&
     pip install --require-hashes -r requirements.txt

Change-Id: I34da4901d08ace3ffe527089ea756e0e667a93cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/5219515
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Commit-Queue: Tzung-Bi Shih <tzungbi@chromium.org>
Tested-by: Tzung-Bi Shih <tzungbi@chromium.org>
6 files changed