FAI 5.8.7 and new ISO images using Debian 10

[Thomas Lange]

A new FAI release is available.

It now supports apt keys in files called
package_config/CLASS.gpg. Before we only supported .asc files.
fai-mirror has a new option -V, which checks if variables are used in
package_config/* and uses variable definitions from class/*.var.

I've also created new ISO images, which now install Debian 10 by
default. They are available from

   https://fai-project.org/fai-cd

If you need a newer kernel, checkout the FAI.me service
(http://fai-project.org/FAIme/) which can also build ISO images using
the kernel from  backports which currently is 5.2.

-- 
regards Thomas