Split `template:alpine` to `template:alpine-{3.21,3.22,3.23}`

Alpine supports multiple minor releases, so `template:alpine` should be split to  `template:alpine-{3.21,3.22,3.23}` as in other distros such as `template:debian-{11,12,13}` and `almalinux-(8,9,10}`.
https://endoflife.date/alpine-linux

https://github.com/lima-vm/lima/blob/master/hack/update-template-alpine.sh needs to be updated to just update the patch release, not the minor release