flags: add root flag
flags: add root flag

coreos/ignition,dgonyeo/ignition,marineam/ignition,marineam/ignition,coreos/ignition,AlexNPavel/ignition,jonboulle/ignition,ajeddeloh/ignition,dgonyeo/ignition,jonboulle/ignition,higebu/ignition,dgonyeo/ignition,crawford/ignition,ajeddeloh/ignition,crawford/ignition,ajeddeloh/ignition,coreos/ignition,marineam/ignition,AlexNPavel/ignition,AlexNPavel/ignition,trnubo/ignition,trnubo/ignition,mischief/ignition,trnubo/ignition,mischief/ignition,jonboulle/ignition,higebu/ignition,higebu/ignition,mischief/ignition