Security Scanning - docker scan removed

[patest-dev]

With the release of Docker Desktop 4.19.0 the docker scan [...] command was removed

The security scanning section should thus be updated to use the docker scout command

See #395

[Paulie420]

Ahhhh - thats the one thing that failed for me... glad I checked the issues; it wasn't a user error afterall!
Thanks for the great tutorial... really taught me the basics of Docker - thanks !!