Bump Security String to 2020-12-05

Implemented:
============
CVE:            References:  Type:  Severity:  Updated AOSP versions:
CVE-2020-0294   A-154915372  EoP    High       8.0, 8.1, 9, 10
CVE-2020-0459   A-159373687  ID     High       8.0, 8.1, 9, 10
CVE-2020-0463   A-169342531  ID     High       8.0, 8.1, 9, 10, 11
CVE-2020-0464   A-150371903  ID     High       10
CVE-2020-0467   A-168500792  ID     High       8.1, 9, 10, 11
CVE-2020-0468   A-158484422  ID     High       10, 11
CVE-2020-0470   A-166268541  ID     High       10, 11
CVE-2020-15802  A-158854097  ID     High       8.0, 8.1, 9, 10, 11

Previously Implemented:
=======================
CVE:            References:  Type:  Severity:  Updated AOSP versions:
CVE-2020-0099   A-141745510  EoP    High       8.0, 8.1, 9, 10
CVE-2020-0458   A-160265164  RCE    Critical   8.0, 8.1, 9, 10

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

Not Applicable (platform source):
=================================
CVE:            References:  Type:  Severity:  Updated AOSP versions:
CVE-2020-0440   A-162627132  EoP    High       11
CVE-2020-0460   A-163413737  ID     High       11
CVE-2020-0469   A-168692734  DoS    High       11

Change-Id: I4172ccf129126f84050e68a14e239b7e03a22a44