Update the link to register with the VTK-m dashboard

The URL changed slightly.
7 jobs for register-dashboard-link
Status Name Job ID Coverage
  External
passed cdash-buildbot

passed vtk-m-dragnipur-osx-shared-debug+32bit_ids+64bit_coords+clang+tbb

00:09:39

passed vtk-m-dragnipur-osx-static-release+64bit_coords+clang+tbb

00:15:49

failed vtk-m-osheim-windows-shared-debug+ninja-vs-2017+tbb

00:00:21

failed vtk-m-osheim-windows-static-release+ninja-vs-2017+tbb

00:03:13

passed cdash-buildbot

failed vtk-m-osheim-windows-shared-debug+ninja-vs-2017+tbb