Install Graphviz in deploy script setup

[melahn]

In order to avoid the

java.io.IOException: Cannot run program "/opt/local/bin/dot": error=2, No such file or directory

install Graphviz in the setup as is done for the build script. This is not causing the deploy to fail since it is not necessary to regenerate images from puml files for deployment, but it's messy to see in the logs.

Specifically, add...

      - name: Install graphviz
        run: sudo apt-get install graphviz

after the checkout step.