docs(logout): include required context in help example

[hazelmayank]

Summary

FIxes #350
This PR fixes the microcks logout --help example.

The command usage requires a CONTEXT argument, but the current example shows:

microcks logout

[Harsh4902]

LGTM

[github-actions]

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[hazelmayank]

Thank you for the review and merge! I’ll continue working on small, focused improvements and gradually move toward deeper CLI reliability / developer experience issues.