chore: pass in fedora version

Containerfile

@@ -1,11 +1,11 @@
 ARG SOURCE_IMAGE=${SOURCE_IMAGE:-base}
 ARG SOURCE_REPO=${SOURCE_REPO:-fedora-ostree-desktops}
 ARG BASE_IMAGE=quay.io/${SOURCE_REPO}/${SOURCE_IMAGE}
-ARG FEDORA_VERSION=${FEDORA_VERSION:-40}
 
 # Build from base-main since its our smallest image and we control the tags
 FROM ${BASE_IMAGE}:${FEDORA_VERSION} as builder
 ARG KERNEL_VERSION=${:-}
+ARG FEDORA_VERSION=${FEDORA_VERSION:-}
 
 COPY fetch.sh /