Description

Add a {current_version} variable to the commit message generation, perhaps consider aliasing the {version} variable with {new_version}.

Use cases

That would allow me to specify a commit message like

commit_subject = "Bump v{current_version} → v{new_version}"

Possible implementation

I think the change needs to be added to commit_new_version() which is called from bump_version() which maybe should get the current version passed in as function argument from its callers where current_version is available.