add tailscale pub key to fix build

Author: sagor999

dev/image/Dockerfile

@@ -21,6 +21,11 @@ RUN mkdir -p /tmp/helm/ \
     && rm -rf /tmp/helm/ \
     && helm completion bash > /usr/share/bash-completion/completions/helm
 
+### temp. do not submit
+RUN curl -fsSL https://pkgs.tailscale.com/stable/ubuntu/focal.gpg | sudo apt-key add - \
+    && curl -fsSL https://pkgs.tailscale.com/stable/ubuntu/focal.list | sudo tee /etc/apt/sources.list.d/tailscale.list \
+    && apt-get update
+
 ### kubernetes ###
 RUN mkdir -p /usr/local/kubernetes/ && \
     curl -fsSL https://github.com/kubernetes/kubernetes/releases/download/v1.22.4/kubernetes.tar.gz \