Docs: fix path to nologin shell

[exsplashit]

• [ ] read the CONTRIBUTING guidelines
• [ ] raised a GitHub issue or discussed it on the projects chat beforehand
• [ ] added unit tests
• [ ] added integration tests
• [x] updated documentation if needed
• [ ] updated CHANGELOG.md

Just small fix to copy-paste tutorial deploy

[ohdearaugustin]

Several locations for nologin do exist:

• /usr/bin/nologin
• /usr/sbin/nologin
• /sbin/nologin

This is mainly dependend on the OS you are using.

Arch: has all three Ubuntu:

• /usr/sbin/nologin
• /sbin/nologin

Rockylinux (RedHat):

• /usr/sbin/nologin
• /sbin/nologin

So I guess the change to /usr/sbin/nologin should make it work on more systems out of the box.