Consider exposing a library version of cargo-bump

[sedrik]

I will be using cargo-bump in my CI/CD setup at work to automatically update the version when a merge to development happens.

Could the functionality of cargo-bump be exposed as a library that I could use instead of having to install and compile it through cargo (the cache I am using for my github actions misses that compilation as it happens outside of the repository).

A cargo workspace with a cargo-bump-lib (lib) and cargo-bump (bin) would be a nice setup for this I believe.

I would probably be able to help with the implementation of such a lib.