How to fix Alpine Linux wg-quick (no such package)

Problem:

While trying to install wg-quick on Alpine Linux, you see the following error message:

ERROR: unable to select packages:
  wg-quick (no such package):
    required by: world[wg-quick]

Solution:

You need to install the wireguard-tools package which also contains wg-quick:

apk add wireguard-tools