version-tools: Add functions to get latest version from list of versions

[tylerbutler]

This PR updates the version-tools based on partner feedback. In particlar, it adds a new version latest command that takes a list of version numbers and returns the most recent version.

fluv version latest

Find the latest version from a list of version strings, accounting for the Fluid internal version scheme.

USAGE
  $ fluv version latest -r <value> [--json] [--prerelease]

FLAGS
  -r, --versions=<value>...  (required) The public version to use in the Fluid internal version.
  --prerelease               Include prerelease versions.

GLOBAL FLAGS
  --json  Format output as json.

DESCRIPTION
  Find the latest version from a list of version strings, accounting for the Fluid internal version scheme.

EXAMPLES
  You can use the --versions (-r) flag multiple times.

    $ fluv version latest -r 2.0.0 -r 2.0.0-internal.1.0.0 -r 1.0.0 -r 0.56.1000

  You can omit the repeated --versions (-r) flag and pass a space-delimited list instead.

    $ fluv version latest -r 2.0.0 2.0.0-internal.1.0.0 1.0.0 0.56.1000