[FEATURE] Add command to get the latest version for CI builds

[marcbull]

Is your feature request related to a problem? Please describe.
For my workflow I use a script to get the latest version for a CI build. It's a combination of cog bump --dry-run --skip-untracked --auto and cog get-version. If bump doesn't return a version the result of `get-version´ is used.

This script always returns a valid version, even if no future version is available or no current version is released (-f 0.0.0).

Describe the solution you'd like
My proposal would be to move this work to cog. It could be a command like ci-version or next-version.

Describe alternatives you've considered
The previously mentioned script.