Consider raising sebastian/diff constraint

Problem/Motivation

We currently support four versions of sebastian/diff:

sebastian/diff": "^4 || ^5 || ^6 || ^7"

In 🐛 Can't update to 11.2.0 Active we changed things so that the core-recommended metapackage allows any version. This is probably OK, but we could consider dropping support for version 4 and/or 5 to have a narrower range of versions to maintain compatibility with.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet