semver filtering and ordering

[squaremo]

For the postgres image (postgres), which has tags representing versions, the timestamps of the images are not in the same order as the versions.

For public images like this, and for people who version their own images, it'd be pretty useful to be able to filter on semver ranges like ^9.4. This would imply an ordering by version as well (i.e., using semver.LessThan` or whatever the library function is).