Add breaking change notice and update travis link

README.md

 # graphene-django-optimizer
 
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+[![build status](https://img.shields.io/travis/tfoxy/graphene-django-optimizer.svg)](https://travis-ci.com/github/tfoxy/graphene-django-optimizer)
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 ![python version](https://img.shields.io/pypi/pyversions/graphene-django-optimizer.svg)
@@ -9,12 +9,14 @@
 Optimize queries executed by [graphene-django](https://github.com/graphql-python/graphene-django) automatically, using [`select_related`](https://docs.djangoproject.com/en/2.0/ref/models/querysets/#select-related), [`prefetch_related`](https://docs.djangoproject.com/en/2.0/ref/models/querysets/#prefetch-related) and [`only`](https://docs.djangoproject.com/en/2.0/ref/models/querysets/#only) methods of Django QuerySet.
 
 
+
 ## Install
 
 ```bash
 pip install graphene-django-optimizer
 ```
 
+*Note: If you are using Graphene V2, please install version `0.8`. v0.9 and forward will support only Graphene V3*
 
 ## Usage