scripts: add gpg to Debian dependencies
scripts: add gpg to Debian dependencies

This is required for the default build and is
included in the Fedora ones.

Shashwatsh/rkt,shobhit85/rkt,kinvolk/rkt,cab105/rkt,joshix/rkt,ybubnov/rkt,rkt/rkt,coreos/rkt,lucasallan/rkt,dgonyeo/rkt,shobhit85/rkt,achanda/rkt,jonboulle/rkt,dgonyeo/rkt,kinvolk/rkt,rkt/rkt,alban/rkt,cab105/rkt,sstabellini/rkt,cab105/rkt,coreos/rkt,jakon89/rkt,lucasallan/rkt,kinvolk/rkt,ybubnov/rkt,shobhit85/rkt,jonboulle/rkt,lucasallan/rkt,rkt/rkt,sstabellini/rkt,intelsdi-x/rkt,alban/rkt,achanda/rkt,joshix/rkt,ybubnov/rkt,joshix/rkt,lucasallan/rkt,intelsdi-x/rkt,jakon89/rkt,rkt/rkt,Shashwatsh/rkt,kinvolk/rkt,intelsdi-x/rkt,joshix/rkt,alban/rkt,sstabellini/rkt,achanda/rkt,dgonyeo/rkt,coreos/rkt,jakon89/rkt,jonboulle/rkt,Shashwatsh/rkt