renovate: Disallow Fedora rawhide

Let's only update to released versions, not to a rawhide one as
happened in #142.

Signed-off-by: Jakob Naucke <[email protected]>

Author: Jakob-Naucke

.github/renovate.json

@@ -1,3 +1,9 @@
 {
+    "packageRules": [
+        {
+            "matchPackageNames": ["quay.io/fedora/fedora"],
+            "allowedVersions": "!/rawhide/"
+        }
+    ],
     "postUpdateOptions": ["gomodTidy"]
 }