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.
Take the last kernel version listed in sha256sums.asc when
multiple versions are listed.
We assume that the patches listed in sha256sums.asc are ordered by
increasing version number.
This does not keep 5.9 series because it has known issues and rt
upstream has stopped maintaining it in favor of 5.10.
"ls -v" sorts by version, making 5.10 the next $prev kernel.