Installation instructions don't work anymore

[cmahnke]

brew is getting worse every day, so the instructions from the README won't work anymore, this seems to be the same conceptual flaw (disguised as "security") that breaks easy downgrading of packages:

Error: Calling Non-checksummed download of sshpass formula file from an arbitrary URL is disabled! Use 'brew extract' or 'brew create' and 'brew tap-new' to create a formula file in a tap on GitHub instead.

This will do the trick:

sudo port install sshpass