update gitpod configuration

install matchbox package to allow the UI to show up when testing

.gitpod.Dockerfile

@@ -2,7 +2,7 @@ FROM gitpod/workspace-full-vnc
 
 USER root
 
-RUN  apt-get update && apt-get install -y matchbox && apt-get clean && rm -rf /var/cache/apt/* && rm -rf /var/lib/apt/lists/* && rm -rf /tmp/*
+RUN sudo apt-get update && sudo apt-get install -y matchbox && sudo apt-get clean && sudo rm -rf /var/cache/apt/* && sudo rm -rf /var/lib/apt/lists/* && sudo rm -rf /tmp/*
 
 USER gitpod