Custom palette tests fail on Windows

[hollowscene]

Five tests fail in test_palettes_custom_palconfig_files.py when test suite is run on Windows.

Here is the full pytest output: pytest_results.txt

For quick access, the error message of one of those test fails:

___________________________________ test_hclpalettes_custom_palconfig_good_custom_div ___________________________________ 

    def test_hclpalettes_custom_palconfig_good_custom_div():

        tmpfile = NamedTemporaryFile()
>       with open(tmpfile.name, "w") as fid: fid.write(good_custom_div)
E       PermissionError: [Errno 13] Permission denied: 'C:\\Users\\andrew\\AppData\\Local\\Temp\\tmpmchuptx8'

This appears to be an OS difference caused by the tempfile package. Old but relevant StackOverflow answer.