dns/opendnssec2: Update t0 2.1.7

ChangeLog: https://www.opendnssec.org/2023/06/opendnssec-2-1-13/

This release fixes a bug that affects both signer and enforcer command
line handling. Under heavy usage of the command line there was a small
change for a crash.
Furthermore there is a small behavioural change for users of the "keep"
policy. The back-off for retrying a sign task change is now equal to
the resign period in case the input file isn't available or updated.
This because users nearly always will emit an external sign command for
this period. This will reduce logging errors.

PR: 272254
Reported by: jaap@NLnetLabs.nl (maintainer)