updating quick start

SUMMARY.md

 # Summary
 
+* [Release Notes](doc/release-notes.md)
+  * [Zefyr Changelog](packages/zefyr/CHANGELOG.md)
 * [Quick Start](doc/quick-start.md)
 * [Concepts](doc/concepts/readme.md)
   * [Data Format and Document Model](doc/concepts/data-and-document.md)

doc/release-notes.md

+# Release notes
+
+Current version of Zefyr editor is `0.7` ([changelog](packages/zefyr/CHANGELOG.md)).
+
+### 0.7
+
+__This is a breaking change release.__
+
+This version introduces first set of changes aimed at addressing some
+common pain points reported by users of this library. In addition this release
+is the first step towards making Zefyr easier to extend and customize.
+
+This version of Zefyr also comes with revamped documentation website and
+some of the articles completely rewritten to help new users to get started. More
+articles and tutorials will be added in future releases.
+
+Highlights of this release include:
+
+* Zefyr no longer depends in `image_picker` package. This introduced breaking
+  changes described in the changelog.
+* Selection overlay has been refactored to enable customization work in
+  follow up releases.
+* Zefyr now supports selection-only workflow via new `ZefyrMode` object which
+  replaces previous `enabled` field (breaking change).
+
+For more details on breaking changes and upgrade instructions please read
+[changelog](packages/zefyr/CHANGELOG.md).