Add changelog note on models ordering change done in 2.0.0
Add changelog note on models ordering change done in 2.0.0

Noticed the ordering of the `Revision` and `Version` models was reversed in 2.0, [in this commit](https://github.com/etianen/django-reversion/commit/8a3a6c369fd4d16253884dd31c98969065d1e26e#diff-848d9ceb3ff77cf47a950aa6c22852daR99). This caused a little confusion when updating, since `.last()` was now `.first()`.
etianen/django-reversion,etianen/django-reversion