ConsensusProposal::changePosition

Update the position during the consensus process.

bool
changePosition(
    Position_t const& newPosition,
    NetClock::time_point newCloseTime,
    NetClock::time_point now);

This will increment the proposal's sequence number.

Name	Description
`newPosition`	The new position taken.
`newCloseTime`	The new close time.
`now`	the time The new position was taken.

true if the position was updated or false if this node has already left this consensus round.