OpenLDAP 2.5 upgrade in bullseye-backports

[Ryan Tandy]

A heads up to anyone using the bullseye-backports version of slapd.

OpenLDAP 2.5.13 is on its way to bullseye-backports (currently waiting 
in NEW). Depending on your configuration, upgrading slapd may require 
manual config updates. If you use automatic upgrades, you may wish to 
pin slapd until you can upgrade it manually.

If you use any of the following backends or modules, you should take 
care with the upgrade:

- back_bdb(5), back_hdb(5)
- back_shell(5)
- slapo-ppolicy(5)
- slapd-pw-argon2(5)

slapd's README.Debian contains information about how to update your 
configuration and complete the upgrade.

https://sources.debian.org/src/openldap/2.5.13%2Bdfsg-2/debian/slapd.README.Debian/#L255-L378

thanks,
Ryan