Optionally use `sphinx_changelog_gen.py` to dump current version of the
API in a JSON file, and use closest previous one listed in given index
file to create a changelog RST page for Sphinx.
Part of {T97663}.
Optionally use `sphinx_changelog_gen.py` to dump current version of the
API in a JSON file, and use closest previous one listed in given index
file to create a changelog RST page for Sphinx.
Part of {T97663}.