update the pgp link for ubuntu installation

[techsupport-cma971]

Replace https://apt.vulns.sexy/kpcyrd.pgp by https://apt.vulns.xyz/kpcyrd.pgp

thanks

Versions

• rustc --version:
• cargo --version:
• sn0int --version:
• uname -a:

Environment

• ubuntu:
• Installed from (source/apt/pacman/brew/docker):