provision-apt-get-install: ensure gpg is installed
provision-apt-get-install: ensure gpg is installed

The basebox installs gpg, but when this script is used to provision
a GitLab CI Runner, gpg was missing.  It is used in some builds.

f-droid/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroid-server,f-droid/fdroidserver,f-droid/fdroidserver,f-droid/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver,f-droid/fdroid-server,f-droid/fdroidserver,f-droid/fdroid-server