[automerger skipped] Update Security String to 2021-01-01 am: 6441bc7c am:...

[automerger skipped] Update Security String to 2021-01-01 am: 6441bc7c am: cc0c1b00 am: 0f0c87ea am: e4144014 am: e4ca3c2e am: 39768724 -s ours am: b2fe3745 -s ours am: c1b6196a -s ours

am skip reason: Change-Id I273073a04d6981c5a58b3aebdf13249fdb46586e with SHA-1 643b2649 is in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/13074489

Change-Id: Icf6df3192b1d5cc1180ec76c7d241ce49942cad7