PrePARE skipping files in Python 3.10 builds

[mauzey1]

When testing PrePARE for Python 3.10, I get the following message for a valid file.

$ PrePARE rlut_Amon_UKESM1-0-LL_histSST-piAer_r1i1p1f2_gn_195001-201412.nc 
<built-in function check_filename> returned a result with an exception set
└──> :: SKIPPED    :: /Users/mauzey1/Desktop/github/cmor/rlut_Amon_UKESM1-0-LL_histSST-piAer_r1i1p1f2_gn_195001-201412.nc

Number of files scanned: 1
Number of file with error(s): 1

What I get with the Python 3.9 version...

$ PrePARE rlut_Amon_UKESM1-0-LL_histSST-piAer_r1i1p1f2_gn_195001-201412.nc 

Number of files scanned: 1
Number of file with error(s): 0

This is an issue that might affect newer versions of Python so we should try fixing this issue before adding a Python 3.11 build (#669).