Add Changelog for the version 2.0

Author: LaurentPetard

CHANGELOG-2.0.md

@@ -0,0 +1,12 @@
+# 2.0.0 (2018-02-15)
+
+## Improvements
+
+- API-487: Isolate files manipulation in a dedicated service
+- API-562: upsert a list of attribute options
+- API-543: Create a new media file and associate it to a product model
+
+## BC Breaks
+
+- Change the constructor of `Akeneo\Pim\ApiClient\Api\ProductMediaFileApi` to add `Akeneo\Pim\ApiClient\FileSystem\FileSystemInterface` 
+- Add method `Akeneo\Pim\ApiClient\Api\AttributeOptionApiInterface::upsertList`