dns/knot-resolver: update 2.3.0 -> 2.4.1

• CVE-2018-10920: Improper input validation bug in DNS resolver component

PR: 229485
Reported by: freebsd-vheg@riseup.net,
Approved by: freebsd@dns.company (maintainer timeout)
MFH: 2018Q3
Relnotes: https://www.knot-resolver.cz/2018-07-03-knot-resolver-2.4.0.html

		https://www.knot-resolver.cz/2018-08-02-knot-resolver-2.4.1.html

Security: CVE-2018-10920