Fix typo

Author: boisgera

README.md

@@ -69,7 +69,7 @@
 
 The course materials are also available as Jupyter notebooks. To execute and edit them:
 
- 0. [Install the pixi package manager](https://pixi.sh/latest/).**
+ 0. [Install the pixi package manager](https://pixi.sh/latest/).
 
  1. Download and extract this [zip archive](https://github.com/boisgera/control-engineering-with-python/archive/refs/heads/gh-pages.zip)[^1]