DOC: Fix `CONTRIBUTING` file link in binary data upload file
DOC: Fix `CONTRIBUTING` file link in binary data upload file

Fix `CONTRIBUTING` file link in binary data upload file.

Take advantage of the commit to add the link to `data.kitware.com` where
previously was not present for a better discoverability.

hjmjohnson/ITK,Kitware/ITK,hjmjohnson/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,Kitware/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,hjmjohnson/ITK,hjmjohnson/ITK,Kitware/ITK