spec: add weldr provide

Since the recent commit (04db4fa) we are no longer provider
of lorax-composer. This was needed because when installing cockpit-composer,
which depends on lorax-composer, dnf chose us as the lorax-composer provider
instead of the original lorax-composer package. As we are not yet ready to
fully replace lorax-composer, this broke the cockpit-composer tests.

This commit is the first part of long term fix. Osbuild-composer is now
a provider of weldr. Soon, lorax-composer will also be a provider of
weldr. After that, cockpit-composer will be switched to be depending
on weldr. Also, it will suggest lorax-composer, which will force dnf
to use lorax-composer as the default weldr backend. If someone wants
to experiment with osbuild-composer, it will be possible, because
it will also be a provider of weldr and there will be no need to
install lorax-composer to satisfy cockpit-composer dependencies.

golang-github-osbuild-composer.spec

@@ -41,6 +41,7 @@ Requires: systemd
 Requires: osbuild >= 7
 
 Provides: osbuild-composer
+Provides: weldr
 
 %description
 %{common_description}