Merge topic 'start-vtk8-release'

345343a4 bump vtk version number for about to be released version

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !2849

CMake/vtkVersion.cmake

 # VTK version number components.
-set(VTK_MAJOR_VERSION 7)
-set(VTK_MINOR_VERSION 1)
+set(VTK_MAJOR_VERSION 8)
+set(VTK_MINOR_VERSION 0)
 set(VTK_BUILD_VERSION 0)