13.2R: Minor corrections to announce and relnotes

• The release date is now known, and thus the EoL date for 13.1 is

known. [1]

• OpenSSH[2] and tzdata[3] got updated one last time before the release.

The signed announce.asc file will not be updated for these corrections.

Reported by: Graham Perrin [1]
Reported by: Jakub Bystron [2]
Reported by: Dan Allen [3]
Reviewed by: delphij
Differential Revision: https://reviews.freebsd.org/D40416