Fix doctest failure due to new version of hpx
The corrected error are of the type:
file "tutorial/skymaps.rst", line ?, in default
Failed example:
credible_levels
Expected:
array([1., 1., 1., ..., 1., 1., 1.])
Got:
array([1., 1., 1., ..., 1., 1., 1.], dtype='>f8')
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Edited by Roberto DePietri