[Backport release-0.8] jumpstarter-driver-gpio: Add read method required by PowerInterface#623

mangelajo merged 1 commit intorelease-0.8jumpstarter-dev/jumpstarter:release-0.8from

backport-616-to-release-0.8jumpstarter-dev/jumpstarter:backport-616-to-release-0.8Copy head branch name to clipboard