styles/ramp.py:258: RuntimeWarning: invalid value encountered in cast

[pjonsson]

Noticed a warning relating to the real code in the unit-integration-performance-tests logs from the CI, so putting it here so it doesn't get lost:

integration_tests/test_wms_server.py::test_wms_multidate_getmap
  /code/datacube_ows/styles/ramp.py:258: RuntimeWarning: invalid value encountered in cast
    return val.astype("uint8")

[SpacemanPaul]

IIRC recent versions of numpy have slightly odd behaviour wrt the uint8 dtype and this was nothing to worry about, but I'll flag it for a revisit and if it is expected behaviour, I'll document it.

[pjonsson]

I searched a bit and ONNX had a similar issue where they casted a negative float number to an unsigned integer, and cftime has a similar issue where they are casting NaNs/infs: Unidata/cftime#328.