security/clamav: update 0.102.3 -> 0.102.4

PR: 248028
Submitted by: Yasuhiro KIMURA <yasu@utahime.org> (maintainer)
MFH: 2020Q3
Relnotes: https://blog.clamav.net/2020/07/clamav-01024-security-patch-released.html
Security: CVE-2020-3350, CVE-2020-3327, CVE-2020-3481