release_python_package.md: Impossible to change major version if the first major was 0

The [documentation](https://github.com/canonical/data-platform-workflows/blob/main/.github/workflows/release_python_package.md) of the release python package specifies that it should start with a minor `v0.1.0`.
However, the workflow will never bump a major version if the initial major version was 0 ([see here](https://github.com/canonical/data-platform-workflows/blob/main/python/cli/data_platform_workflows_cli/create_semantic_version_tag.py#L77)).

It would be great to have a way to forcefully bump the major in that case, or remove the check `last_version.major > 0` from the first test so that it's possible to bump the major in that case as well.

Read .github/workflows/release_python_package.md and python/cli/data_platform_workflows_cli/create_semantic_version_tag.py around line 77. Compare the documented v0.1.0 starting point with the major-version condition, then determine the intended behavior for moving from major version 0 to 1. Done when the workflow behavior and its documentation agree.

Written by the indexing model from the issue text.