Bump Security String to 2021-09-05

Implemented:
============
CVE:            References:  Type:  Severity:  Updated AOSP versions:
CVE-2021-0598   A-180422108  EoP    High       8.1, 9, 10, 11
CVE-2021-0682   A-159624555  ID     High       8.1, 9, 10, 11
CVE-2021-0683   A-185398942  EoP    High       8.1, 9, 10, 11
CVE-2021-0684   A-179839665  EoP    High       8.1, 9, 10, 11
CVE-2021-0687   A-188913943  DoS    Critical   8.1, 9, 10, 11
CVE-2021-0688   A-161149543  EoP    High       8.1, 9, 10, 11
CVE-2021-0689   A-190188264  ID     High       8.1, 9, 10, 11
CVE-2021-0690   A-182152757  ID     High       8.1, 9, 10, 11

Previously Implemented:
=======================
CVE:            References:  Type:  Severity:  Updated AOSP versions:  Prior Change:
CVE-2021-0595   A-177457096  EoP    High       8.1, 9, 10, 11          9d0c9eb59742

Not Implemented:
================
None

Not Applicable (platform source):
=================================
CVE:            References:  Type:  Severity:  Updated AOSP versions:
CVE-2021-0428   A-173421434  ID     High       10
CVE-2021-0644   A-181053462  ID     High       10, 11
CVE-2021-0685   A-191055353  EoP    High       11
CVE-2021-0686   A-177927831  ID     High       10, 11
CVE-2021-0691   A-188554048  EoP    Moderate   11
CVE-2021-0692   A-179289753  EoP    High       9, 10, 11
CVE-2021-0693   A-184046948  ID     High       11

Change-Id: I52a0546516f6d9888069ae18b47648e99e4209fd