fix(fedora): repoint remote to gsl-syd (rackspace dropped F44)

Rackspace (syd.mirror.rackspace.com) never synced Fedora 44: it serves
releases/43 but 404s on releases/44/.../repomd.xml, breaking dnf makecache
for F44 through the caching proxy. Repoint to gsl-syd.mm.fcix.net, a
Sydney-local FCIX tier-1 mirror that is fully synced for F44 (releases +
updates + Packages, verified 200, ~25ms), using the standard
/fedora/linux layout root.

config/remote_rpm/fedora.yaml

@@ -1,4 +1,4 @@
-base_url: https://syd.mirror.rackspace.com/fedora
+base_url: https://gsl-syd.mm.fcix.net/fedora/linux
 description: Fedora Linux RPM package repository
 immutable_ttl: 0
 mutable_ttl: 7200