add requirements.txt for dicom_viewer plugin
add requirements.txt for dicom_viewer plugin

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