package/asterisk: security bump to version 16.2.1
Fixes the following security issue:
AST-2019-001: Remote crash vulnerability with SDP protocol violation
When Asterisk makes an outgoing call, a very specific SDP protocol violation
by the remote party can cause Asterisk to crash (CVE-2019-7251)
https://downloads.asterisk.org/pub/security/AST-2019-001.html
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>