Add shorthand flag -p for --publish option in generate command

[Venkatesh1505]

Description

Add -p as a shorthand flag for --publish in the generate command, consistent with how other flags like --output (-o), --file (-f), and --image (-i) already have shorthand versions.

What does this PR do?

This change adds a single-character shorthand -p for the --publish flag in score-compose generate, making it quicker to use from the command line.

Before: score-compose generate score.yaml --publish 8080:my-workload:80
After: score-compose generate score.yaml -p 8080:my-workload:80

Resolves #445

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• New chore (expected functionality to be implemented)

Checklist:

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• I've signed off with an email address that matches the commit author.

[mathieu-benoit]

LGTM, thanks for your contribution, @Venkatesh1505!

[mathieu-benoit]

JFYI, associated doc now updated accordingly too: score-spec/docs#265, thanks again!