Install rsync in the container (#76)

This simplifies the workflow file and speeds up every deploy.

mono.Dockerfile

@@ -12,6 +12,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     unzip \
     wget \
     zip \
+    rsync \
     && rm -rf /var/lib/apt/lists/*
 
 # When in doubt see the downloads page