ci: add changelogs to automated version updates

Add the links to the changelogs of the freshly updated components to the
automated PR that does the update. This allow verifying that we are not
missing any important changes before merging the update. This happened
recently with node-exporter 1.2 which changed some flag names that we
took 3 months to update.

Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>