Output the next version for components

## Is your feature request related to a problem? Please describe

I'd like to be able to get the next version of a component that release please will create a release for, based on the currently open PR.

For example, when I merge to main and release please opens a PR, I can get the `prs` from the outputs, but there is no way to get just the next version of a component.

## Describe the solution you'd like

I'd like a new variable `next_version` to be included in the outputs for root and path components when `release_created` for that component is `false`.

## Describe alternatives you've considered

The only real alternative is to try and extract the next version from the `prs` output. However, this is not reliable because if release please doesn't update the PR, the output is omitted.

## Additional context

There is a scenario where only e.g. `chore` commits have been pushed and release please has not yet created a PR. In that case, I would suggest that the next patch version should be output as `next_version` for root and path components.

Start by tracing how the action currently builds the prs and release_created outputs for root and path components. Define done as exposing next_version for components without a created release, including the suggested next patch version when only chore commits exist; verify the output behavior with the repository's existing tests.

Written by the indexing model from the issue text.