Description

Just display the next version based on commits:

# before this PR: 4.16.5
$ cz version -p --next
4.17.0
$ cz version -p --next --minor
17
$ cz version -p --next --major
4

This is useful, because it improves the scm provider workflow, which is read-only, based on the tag.
With this features users can easily write themselves:

next_version = $(cz version -p --next --tag)
git tag "$next_version"

TODO: Add tutorial for this

On top of that, it's useful for github/forgejo actions for example (not controlled by commitizen, so you'd still need to format the tag):

next_major = $(cz version -p --next --major)
git tag -f "v$next_major"

Checklist

• I have read the contributing guidelines

Was generative AI tooling used to co-author this PR?

• Yes (please specify the tool below)

AI only assisted with testing

Code Changes

• Add test cases to all the changes you introduce
• Run uv run poe all locally to ensure this change passes linter check and tests
• Manually test the changes:
  • Verify the feature/bug fix works as expected in real-world scenarios
  • Test edge cases and error conditions
  • Ensure backward compatibility is maintained
  • Document any manual testing steps performed
• Update the documentation for the changes

Documentation Changes

• Run uv run poe doc locally to ensure the documentation pages renders correctly
• Check and fix any broken links (internal or external)

Expected Behavior

Steps to Test This Pull Request

# before this PR: 4.16.5
$ cz version -p --next
4.17.0
$ cz version -p --next --minor
17
$ cz version -p --next --major
4

Additional Context