add Christophe Creeten to the README
add Christophe Creeten to the README

ftomassetti/java-symbol-solver,xdrop/java-symbol-solver,javaparser/javasymbolsolver,rpau/java-symbol-solver,rpau/java-symbol-solver,ftomassetti/java-symbol-solver,javaparser/javasymbolsolver,xdrop/java-symbol-solver