Install tree tool in conan-training dockerfile (#117)

Author: danimtb

docker_images/conan-training/Dockerfile

@@ -32,6 +32,7 @@ RUN apt-get update && apt-get install -y \
     fonts-noto-color-emoji \
     python3-pip \
     python3-venv \
+    tree \
     file && \
     rm -rf /var/lib/apt/lists/*