Update to Conventional changelog 3.1.x

[jaszczw]

Updates the reference to new conventional-changelog core. Adjusts preset option passing as it has changed between releases.

Adds ability to configure preset from config.

[hutson]

@jaszczw do these same changes need to be made to the conventional-gitlab-releaser package as well?

[jaszczw]

@hutson the conventional-gitlab-releaser will work as it's using conventional-changelog as dependency, and in the PR I've added a check if preset is passed as string or object - so conventional-gitlab-releaser referencing the freshest version of conventional-changelog should be fine without any changes.