Merge branch 'upstream-diy2' into HEAD

ThirdParty/diy2/vtkdiy2/README.md

ThirdParty/diy2/vtkdiy2/include/vtkdiy/algorithms.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/constants.h

ThirdParty/diy2/vtkdiy2/include/vtkdiy/critical-resource.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/decomposition.hpp

...diy2/include/vtkdiy/detail/algorithms/kdtree-sampling.hpp

.../diy2/vtkdiy2/include/vtkdiy/detail/algorithms/kdtree.hpp

...ty/diy2/vtkdiy2/include/vtkdiy/detail/algorithms/sort.hpp

.../diy2/vtkdiy2/include/vtkdiy/detail/reduce/all-to-all.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/io/block.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/io/bov.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/io/numpy.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/link.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/master.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/mpi/collectives.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/mpi/optional.hpp

...Party/diy2/vtkdiy2/include/vtkdiy/partners/all-reduce.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/partners/common.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/partners/merge.hpp

ThirdParty/diy2/vtkdiy2/include/vtkdiy/partners/swap.hpp