Set snapshot release to "latest"

See relevant docs at
https://github.com/softprops/action-gh-release?tab=readme-ov-file#-customizing

It's necessary to remove the "prerelease" option since a prerelease
build can't be designated as the latest.

(I was hoping to prevent the rolling release from being pushed down
the page every time a new release is created, but it looks like
that's still happening. It seems reasonable to designate the rolling
release as the latest, so let's keep this change anyhow.)

Ref: https://issues.redhat.com/browse/EC-602

Author: simonbaird

.github/workflows/release.yaml

@@ -175,7 +175,7 @@ jobs:
       - name: Rolling release
         uses: softprops/action-gh-release@9d7c94cfd0a1f3ed45544c887983e9fa900f0564 # v2.0.4
         with:
-          prerelease: true
+          make_latest: true
           name: Rolling release
           body: Stable rolling release. Version can be determined by running `ec version`.
           tag_name: snapshot