gui: fix typo in readme
gui: fix typo in readme

Signed-off-by: Peter Gadfort <7a938094a14a6d7745b59a60224c4a3a5eb6a3d8@army.mil>

QuantamHD/OpenROAD,The-OpenROAD-Project/OpenROAD,QuantamHD/OpenROAD,QuantamHD/OpenROAD,The-OpenROAD-Project/OpenROAD,The-OpenROAD-Project/OpenROAD,The-OpenROAD-Project/OpenROAD,QuantamHD/OpenROAD,QuantamHD/OpenROAD,The-OpenROAD-Project/OpenROAD