no Branch chaostoolkit exists

[JeeKayPee]

On the main page
https://github.com/MrBW/chaos-monkey-spring-boot-demo
the instructions say the following
git clone https://github.com/MrBW/chaos-monkey-spring-boot-demo.git
git checkout chaostoolkit

while executing git checkout chaostoolkit
the following error is reported
ubuntu@ip-172-31-22-175:~$ git checkout chaostoolkit
fatal: not a git repository (or any of the parent directories): .git

if I run the command in the chaos-monkey-spring-boot-demo folder, then the following is reported
ubuntu@ip-172-31-22-175:$ cd chaos-monkey-spring-boot-demo/
ubuntu@ip-172-31-22-175:/chaos-monkey-spring-boot-demo$ git checkout chaostoolkit
error: pathspec 'chaostoolkit' did not match any file(s) known to git

Please advise on the next steps