Update README header

adds logo and HTML formatting

README.md

@@ -1,7 +1,22 @@
-# [iNNvestigate neural networks!](https://github.com/albermax/innvestigate) [![Tweet](https://img.shields.io/twitter/url/http/shields.io.svg?style=social)](https://twitter.com/intent/tweet?text=iNNvestigate%20neural%20networks!&url=https://github.com/albermax/innvestigate&hashtags=iNNvestigate,artificialintelligence,machinelearning,deeplearning,datascience)
+<div align="center">
+  <a href="https://github.com/albermax/innvestigate/">
+    <img
+      src="docs/assets/logo.svg"
+      alt="iNNvestigate Logo"
+      height="100"
+    />
+  </a>
+  <br />
+  <p>
+    <h1>
+      <b>
+        iNNvestigate neural networks!
+      </b>
+    </h1>
 
 [![Documentation](https://img.shields.io/badge/Documentation-stable-blue.svg)](https://innvestigate.readthedocs.io/en/latest/)
 [![Build Status](https://github.com/albermax/innvestigate/actions/workflows/ci.yml/badge.svg)](https://github.com/albermax/innvestigate/actions/workflows/ci.yml)
+[![Tweet](https://img.shields.io/twitter/url/http/shields.io.svg?style=social)](https://twitter.com/intent/tweet?text=iNNvestigate%20neural%20networks!&url=https://github.com/albermax/innvestigate&hashtags=iNNvestigate,artificialintelligence,machinelearning,deeplearning,datascience)
 
 [![PyPI package version](https://img.shields.io/pypi/v/innvestigate)](https://pypi.org/project/innvestigate/)
 [![GitHub package version](https://img.shields.io/github/v/tag/albermax/innvestigate)](https://github.com/albermax/innvestigate/tags)
@@ -13,6 +28,9 @@
 
 ![Different explanation methods on ImageNet.](https://github.com/albermax/innvestigate/raw/master/examples/images/analysis_grid.png)
 
+  </p>
+</div>
+
 ## Table of contents
 
 * [Introduction](#introduction)
@@ -205,4 +223,4 @@ please open an issue or submit a pull request.
 
 ## Acknowledgements
 
-> Adrian Hill acknowledges support by the Federal Ministry of Education and Research (BMBF) for the Berlin Institute for the Foundations of Learning and Data (BIFOLD) (01IS18037A).
+> Adrian Hill acknowledges support by the Federal Ministry of Education and Research (BMBF) for the Berlin Institute for the Foundations of Learning and Data (BIFOLD) (01IS18037A).