Update Dockerfile

scripts/install_shiny_server.sh

@@ -8,6 +8,14 @@ if [ "$SHINY_SERVER_VERSION" = "latest" ]; then
     SHINY_SERVER_VERSION=$(wget -qO- https://download3.rstudio.org/ubuntu-18.04/x86_64/VERSION)
 fi
 
+# get the package
 wget --no-verbose "https://download3.rstudio.org/ubuntu-18.04/x86_64/shiny-server-${SHINY_SERVER_VERSION}-amd64.deb" -O /tmp/shiny.deb
+
+# update in order to check signature, needed in jammy
+apt-get update
+# install the package
 apt install -n /tmp/shiny.deb
+
+#cleanup
+rm -rf /var/lib/apt/lists/*
 rm /tmp/shiny.deb