Remove Twitter badge from README (#105)

Author: alessandrofelder

README.md

@@ -9,7 +9,6 @@
 [![Imports: isort](https://img.shields.io/badge/%20imports-isort-%231674b1?style=flat&labelColor=ef8336)](https://pycqa.github.io/isort/)
 [![pre-commit](https://img.shields.io/badge/pre--commit-enabled-brightgreen?logo=pre-commit&logoColor=white)](https://github.com/pre-commit/pre-commit)
 [![Contributions](https://img.shields.io/badge/Contributions-Welcome-brightgreen.svg)](https://brainglobe.info/community/developers/index.html)
-[![Twitter](https://img.shields.io/twitter/follow/brain_globe?style=social)](https://twitter.com/brain_globe)
 
 # brainglobe-heatmap
 `brainglobe-heatmap` allows you to create heatmaps, mapping scalar values for each brain region (e.g., number of labelled cells in each region) to a color and creating visualizations in 2D (using [matplotlib](https://matplotlib.org/) or 3D (using [brainrender](https://brainglobe.info/documentation/brainrender/index.html)).