contrib: actions: remove surplus package sources

contrib/actions/install-dependencies.sh

 #!/bin/bash
 sudo cp contrib/actions/sources.list /etc/apt/sources.list
+sudo rm -rf /etc/apt/sources.list.d
 sudo apt update
 sudo apt install git subversion build-essential python gawk unzip libncurses5-dev zlib1g-dev libssl-dev wget time || exit 1
 sudo apt clean