BUG: restoring libPNG branch name for UpdateFromUpstream.sh
BUG: restoring libPNG branch name for UpdateFromUpstream.sh

The change was accidental commit in
b644f1a3818c9dbbc9aa5751a311f01a109f4174.

richardbeare/ITK,BRAINSia/ITK,LucasGandel/ITK,LucasGandel/ITK,malaterre/ITK,LucasGandel/ITK,Kitware/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,malaterre/ITK,malaterre/ITK,vfonov/ITK,thewtex/ITK,thewtex/ITK,vfonov/ITK,richardbeare/ITK,hjmjohnson/ITK,hjmjohnson/ITK,vfonov/ITK,malaterre/ITK,malaterre/ITK,Kitware/ITK,Kitware/ITK,vfonov/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,hjmjohnson/ITK,BRAINSia/ITK,richardbeare/ITK,vfonov/ITK,LucasGandel/ITK,Kitware/ITK,thewtex/ITK,richardbeare/ITK,BRAINSia/ITK,BRAINSia/ITK,malaterre/ITK,vfonov/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,vfonov/ITK,Kitware/ITK,hjmjohnson/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,richardbeare/ITK,LucasGandel/ITK,malaterre/ITK,BRAINSia/ITK,BRAINSia/ITK,LucasGandel/ITK,malaterre/ITK,thewtex/ITK,hjmjohnson/ITK,thewtex/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,Kitware/ITK,thewtex/ITK,vfonov/ITK,hjmjohnson/ITK,vfonov/ITK,thewtex/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK