additionalChangelog CLI option

[SimonFischer04]

This adds a new optional cli option to the changelog plugin to specify (additional) changelog information directly from the cli, without adding it first to the WIP section in the README/Changelog file.

Why would this be useful: We currently plan on adding automatic releases to the iobroker-esphome adapter after a dependency change. (More information here: https://github.com/DrozmotiX/ioBroker.esphome/issues/118) Having this would allow to just run the release-script and add the dynamic release-information automatically without having to parse / update the README twice (adding release-info to WIP and then change again using release-script). And I think this could also be useful for other projects with CI stuff.