knot: Update to 2.9.5

knot: Update to 2.9.5

For details see:
https://www.knot-dns.cz/2020-05-25-version-295.html

"Bugfixes:

 Old ZSK can be withdrawn too early during a ZSK rollover if maximum
 zone TTL is computed automatically
 Server responds SERVFAIL to ANY queries on empty non-terminal nodes

Improvements:

 Also module onlinesign returns minimized responses to ANY queries
 Linking against libcap-ng can be disabled via a configure option"

Signed-off-by: Matthias Fischer <matthias.fischer@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>