socat: security bump to version 2.0.0-b9

Fixes:
Socat security advisory 7 and MSVR-1499: "Bad DH p parameter in OpenSSL"
Socat security advisory 8: "Stack overflow in arguments parser"

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>