[hotfix] add new streampipes overview in README
<h4 align="center">StreamPipes is a self-service (Industrial) IoT toolbox to enable non-technical users to connect
, analyze and explore IoT data streams. </h4>
<p align="center">
- <img src="https://streampipes.apache.org/img/screenshots/pipeline-editor-2.png" alt="StreamPipes Pipeline
+ <img src="https://streampipes.apache.org/img/screenshots/streampipes-overview.png" alt="StreamPipes Pipeline
Editor"/>
</p>
