Update the link to CONTRIBUTING from README
Update the link to CONTRIBUTING from README

adsorensen/girder,RafaelPalomar/girder,Kitware/girder,RafaelPalomar/girder,Kitware/girder,Xarthisius/girder,jbeezley/girder,manthey/girder,jbeezley/girder,RafaelPalomar/girder,Xarthisius/girder,adsorensen/girder,RafaelPalomar/girder,kotfic/girder,manthey/girder,adsorensen/girder,girder/girder,kotfic/girder,manthey/girder,kotfic/girder,data-exp-lab/girder,adsorensen/girder,Xarthisius/girder,data-exp-lab/girder,jbeezley/girder,girder/girder,Xarthisius/girder,RafaelPalomar/girder,data-exp-lab/girder,manthey/girder,Kitware/girder,adsorensen/girder,jbeezley/girder,data-exp-lab/girder,Xarthisius/girder,girder/girder,Kitware/girder,girder/girder,kotfic/girder,kotfic/girder,data-exp-lab/girder