Bump Security String to 2021-06-05

Implemented:
============
CVE:            References:     Type:   Severity:       Updated AOSP versions:
CVE-2021-0478   A-169255797     EoP     High            8.1, 9, 10, 11
CVE-2021-0507   A-181860042     RCE     Critical        8.1, 9, 10, 11
CVE-2021-0516   A-181660448     EoP     Critical        8.1, 9, 10, 11
CVE-2021-0506   A-181962311     EoP     High            8.1, 9, 10, 11

Previously Implemented:
============
CVE:            References:     Type:   Severity:       Updated AOSP versions:
CVE-2020-26555  A-174626251     EoP     High            8.1, 9, 10, 11
CVE-2020-26558  A-174886838     EoP     High            8.1, 9, 10, 11

Not Implemented:
================
CVE:            References:     Type:   Severity:       Updated AOSP versions:
None

Not Applicable (platform source):
=================================
CVE:            References:     Type:   Severity:       Updated AOSP versions:
CVE-2021-0504   A-179162665     ID      High            11
CVE-2021-0505   A-179975048     EoP     High            11
CVE-2021-0508   A-176444154     EoP     High            8.1, 9, 10, 11
CVE-2021-0509   A-176444161     EoP     High            8.1, 9, 10, 11
CVE-2021-0510   A-176444622     EoP     High            8.1, 9, 10, 11
CVE-2021-0511   A-178055795     EoP     High            9, 10, 11
CVE-2021-0513   A-156090809     EoP     High            8.1, 9, 10, 11
CVE-2021-0517   A-179053823     ID      High            11
CVE-2021-0520   A-176237595     EoP     High            10, 11
CVE-2021-0521   A-174661955     ID      High            8.1, 9, 10, 11
CVE-2021-0522   A-174182139     ID      High            9, 10, 11
CVE-2021-0523   A-174047492     EoP     High            10, 11

Signed-off-by: L.W.Reek <syphyr@gmail.com>

Change-Id: I2fd89473e2eab2769f34e9de20d5b3c7531a6fe7