Instead of having a static repository checksum, set it dynamically from
the metadata that osbuild-composer last saw. This is implemented in
dnf-json, which returns the checksums for each repository on every call.
This enables the use of repositories that change over time, such as
fedora-updates. Note that the osbuild pipeline will break when such a
repository changes. This is intentional: pipelines have to be
reproducible.
d3a0b788a2