linux-rt: Fix incorrect sorting of kernel version numbers when determining latest version

When determining the latest linux-rt kernel version to update to, the list of filenames that `update-rt.sh` fetches from upstream is sorted lexicographically, while `update-rt.sh` assumes it's sorted in version order.  As a result, for example, 5.10.78 is considered newer than 5.10.100.  This change applies `sort --version-sort` to the extracted version numbers to properly identify the latest version.

pkgs/os-specific/linux/kernel/update-rt.sh

@@ -38,6 +38,7 @@ latest-rt-version() {
     curl -sL "$mirror/projects/rt/$branch/sha256sums.asc" |
         sed -ne '/.patch.xz/ { s/.*patch-\(.*\).patch.xz/\1/p}' |
         grep -v '\-rc' |
+        sort --version-sort |
         tail -n 1
 }