Interface to test and compare Excel files (.xls/.xlsx).

Changes for 1.54 - 2024-02-12T11:00:00Z

• Upgraded dependency on Spreadsheet::ParseXLSX v0.31 and Spreadsheet::ParseExcel v0.66 to pull the fix for CVE-2023-7101. blogs.perl.org/users/timothy_l…
• Updated copyright year.
• Tidied up unit test slightly.