knot: Update to 3.0.6

knot: Update to 3.0.6

For details see:
https://www.knot-dns.cz/2021-05-12-version-306.html

"Features:

        mod-probe: new module for simple traffic logging (Python API not yet included)

Improvements:

        keymgr: new mode for listing zones with at least one key stored
        keymgr: the pregenerate command accepts optional timestamp-from parameter
        kzonecheck: accept '-' as substitution for standard input #727
        knotd: print an error when unable to change owner of a logging file
        knotd: new warning log if no interface is configured
        knotd: new signing policy check for NSEC3 iterations higher than 20
        knotd: don't allow backup to/restore from the DB storage directory
        Various code (mostly zone backup/restore), tests, and documentation improvements

Bugfixes:

        knotd: secondary fails to load zone file if HTTPS or SVCB record is present #725
        knotd: (KSK roll-over) new KSK is not signing DNSKEY long enough before DS submission
        knotd: (KSK roll-over) old KSK uselessly published after roll-over finished
        knotd: malformed address in TCP-related logs when listening on a UNIX socket
        knotd: server responds FORMERR instead of BADTIME if TSIG signed time is zero #730
        modules: incorrect local and remote addresses in the XDP mode
        modules: failed to read configuration from a section without identifiers
        mod-synthrecord: queries on synthesized empty-non-terminals not answered with NODATA
        keymgr: confusing error if del-all-old command fails"

For 3.0.5 (skipped):
https://www.knot-dns.cz/2021-03-25-version-305.html

Signed-off-by: Matthias Fischer <matthias.fischer@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>