fix(Dockerfile): adding the tree command to fix a bug with the scripting tests

sh/tests/Dockerfile

@@ -1,7 +1,7 @@
 FROM docker.01-edu.org/debian:10.9-slim
 
 RUN apt-get update
-RUN apt-get -y install jq curl
+RUN apt-get -y install jq curl tree
 
 WORKDIR /app/assets/superhero
 RUN curl --remote-name --location https://demo.01-edu.org/assets/superhero/all.json