Update readme.md
Fixed first line typo
[![License](https://img.shields.io/github/license/spotify/docker-client.svg)](LICENSE)
This is a [Docker](https://github.com/docker/docker) client written in Java.
-It is used it in many critical production systems at Spotify.
+It is used in many critical production systems at Spotify.
* [Version compatibility](#version-compatibility)
* [Download](#download)
