Document the bump to gateway API 1.1.0 as a breaking change

[georgethebeatle]

Background

When it comes to newtowking Korifi has two important dependencies - contour as an ingress implementation and gateway-api as an ingress api. There was a recent bump to contour v1.30.0, in which Contour updates its own dependency to the gateway-api to v1.1.0, which contains a breaking change. Accoding to the docs the user needs to delete the v1alpha2 and/or older versions of the BackendTLSPolicy CRD before installing the new version.

Action to take

In our next release we should document this bump as a breaking change pointing the users to the migration docs of the gateway-api. Korifi is gererall unaffected by this since it does not make uese of the BackendTLSPolicy CRD at all, but we should warn our users to use caution since deleting a custom resource definition will delete all its instances which may affect non-Korifi cluster configurations they might have