Update Gitpod Dockerfile

Author: devlights

.gitpod.Dockerfile

@@ -20,3 +20,6 @@ RUN curl -fsSL https://dl.google.com/go/go${GO_VERSION}.linux-amd64.tar.gz | tar
     go install -v golang.org/x/tools/gopls@latest && \
     printf '%s\n' 'export GOPATH=/workspace/go' \
                       'export PATH=$GOPATH/bin:$PATH' > $HOME/.bashrc.d/300-go
+
+RUN sudo apt update && sudo apt install -y universal-ctags tree
+