Fixes finding HDF5 header

[Julius-Plehn]

Without this PR, only the first file within the loop is checked for. Therefore, it fails if the first file is not found.

Without PR:

-- Checking for HDF5 config header
-- Looking for H5public.h
-- Looking for H5public.h - not found
CMake Error at cmake/check_hdf5.cmake:30 (message):
  Could not include any HDF5 config headers
Call Stack (most recent call first):

With PR:

-- Looking for H5public.h
-- Looking for H5public.h - not found
-- Looking for H5pubconf.h
-- Looking for H5pubconf.h - found
-- Using H5pubconf.h to check for feature macros

[CLAassistant]

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