- update to 20.2:
* Fixed a bug in signing unsigned shim EFI binaries.
* We now build an early microcode initrd in the mkosi kernel-
install plugin.
* Added `PackageDirectories=` to allow providing extra packages
to be made available during the build.
* Fixed issue where `KernelModulesIncludeHost` was including
unnecessary modules
* Fixed `--mirror` specification for CentOS (and variants) and
Fedora.
* Previously a subdirectory within the mirror had to be
specified which prevented using CentOS and EPEL repositories
from the same mirror. Now only the URL has be specified.
* We now mount package manager cache directories when running
scripts on the host so that any packages installed in scripts
are properly cached.
* We don't download filelists on Fedora anymore
* Nested build sources don't cause errors anymore when trying
to install packages.
* We don't try to build the same tools tree more than once
anymore when building multiple images.
* We now create the `/etc/mtab` compatibility symlink in
mkosi's sandbox.
* We now always hash the root password ourselves instead of
leaving it to `systemd-firstboot`.
* `/srv` and `/mnt` are not mounted read-only anymore during
builds.
* Fixed a crash when running mkosi in a directory with fewer
than two parent directories.
* Implemented `RepositoryKeyCheck=` for apt-based