Support config filter 2.x

Problem/Motivation

The 2.x dependency Config Filter has both a 1.x release and a 2.x release.
Both have a 100% compatible API but behave differently when it comes to how they make filter plugins integrate with the configuration management workflow.

Proposed resolution

Add 2.x in the composer require section.

Remaining tasks

commit

User interface changes

n/a

API changes

n/a

Data model changes

n/a

Release notes snippet

Compatible with config_filter 2.x