Updates readme link for demo server wiki page, closes #4773
Updates readme link for demo server wiki page, closes #4773

felixguendling/osrm-backend,Project-OSRM/osrm-backend,yuryleb/osrm-backend,felixguendling/osrm-backend,yuryleb/osrm-backend,frodrigo/osrm-backend,bjtaylor1/osrm-backend,yuryleb/osrm-backend,KnockSoftware/osrm-backend,bjtaylor1/osrm-backend,KnockSoftware/osrm-backend,bjtaylor1/osrm-backend,KnockSoftware/osrm-backend,oxidase/osrm-backend,frodrigo/osrm-backend,oxidase/osrm-backend,yuryleb/osrm-backend,KnockSoftware/osrm-backend,oxidase/osrm-backend,oxidase/osrm-backend,Project-OSRM/osrm-backend,bjtaylor1/osrm-backend,Project-OSRM/osrm-backend,felixguendling/osrm-backend,frodrigo/osrm-backend,Project-OSRM/osrm-backend,frodrigo/osrm-backend