tier-1: inherit from tier-x

We want tier-1 to be another consumer of tier-x, kind of like its own
top-level Fedora variant. That way, tier-1 is now a strict superset of
tier-x, just like the other variants.

tier-1/manifest.yaml

@@ -2,7 +2,7 @@
 recommends: true
 
 include:
-  - ../tier-0/manifest.yaml
+  - ../tier-x/manifest.yaml
   - autoupdates.yaml
   - bootable-rpm-ostree.yaml
   - podman.yaml