security/py-pwntools: Disable generic CLI shortcuts

Use --only-use-pwn-command to prevent installing 'main', 'version',
'errno', etc., reducing $PATH clutter and namespace pollution.

Upstream plans to remove most generic scripts in 5.0.0, which should
further reduce spurious entitlement claims on the system PATH, unlike
the reporter’s ex-wife.

Upstream issue:
https://github.com/Gallopsled/pwntools/issues/2589

PR: 287992
Reported by: milios@ccsys.com