echo "deb [arch=amd64] https://repo.skype.com/deb stable main" > /etc/apt/sources.list.d/skype-stable.list
wget -O - https://repo.skype.com/data/SKYPE-GPG-KEY | sudo apt-key add -
apt-get update && apt-get install skypeforlinux
The installation also updates or recreates the source list file skype-stable.list.