[Opendnssec-maintainers] Release OpenDNSSEC 2.1.8

[(Berry) A.W. van Halderen]

Version 2.1.8 of OpenDNSSEC has been released today, 20/Februari/2021.

This release of 2.1.8 fixes a number of bugs related to the purging of
keys, a potential denial of service vulnerability in some installations,
and a few rarer but nasty potential crashes.  Earlier versions of
OpenDNSSEC 2.1 might not have all keys purged from the HSM if instructed
to do so.  Since this is now done automatically this is worth pointing out
that this was a bug and old keys will be permanently removed from the HSM.

Either when manually purging keys, or having specified a <Purge> in
your key policy (kasp.xml), the keys are supposed to be removed from
the HSM.  However, for some time, the keys were marked for deletion,
and became invisible, but the removal from the HSM was skipped.  In this
release candidate this is fixed, but still allowing keys not to be
removed entirely.  When you specify an automatic purge then the keys
will, after the specified period, will be completely removed.  When you
purge manually, keys are not removed from the HSM unless you specify an
additional flag (the --delete or -d flag).

Special thanks to the people that help us in making OpenDNSSEC better
and better, mentioned in the NEWS file as always.  Two of the bugs
were only traceable using this help.

The 2.1.8 release is available immediately from the download site.

- https://dist.opendnssec.org/source/opendnssec-2.1.8.tar.gz
  SHA256: 900a213103ff19a405e446327fbfcea9ec13e405283d87b6ffc24a10d9a268f5

Issues:
* OPENDNSSEC-954: Upgrade autoconf/automake configuration chain for
  version 2.69/1.16.2.
* SUPPORT-261: Fix to crash when using ods-enforcer set-policy command.
* OPENDNSSEC-953: Fix to crash in case zone file not present while getting
  a signconf update and state flush command.
  Thanks to Stefan Ubbink from SIDN for the co-operation in this fix.
* OPENDNSSEC-951: Modify the purging of keys, to make it automatic to purge
  keys from the HSM.
  Thanks to Stefan Ubbink from SIDN for the co-operation in this fix.
* OPENDNSSEC-950: Fix that caused crash when signer was offline for a
  prolonged period (but the enforcer wasn't) in the middle of a ZSK roll.
* OPENDNSSEC-952: memory leak in when receiving NOTIFY for non-existent zone
  Thanks Sébastien Tisserant to for reporting).