p5-Spreadsheet-Read: update to 0.81.

0.81 - 25 Aug 2019, H.Merijn Brand
    * It's 2019
    * Allow -c + --sep in xlscat
    * Add --sep= to xls2csv for -A
    * Add xlsx2csv to distribution (xlsx2csv has -A)
    * Add -J s / --join str to xlsx2csv
    * Add cpanfile
    * Add explicit documentation about formatted vs unformatted
    * Improve ->new behavior
    * Auto-detect fallback for CSV now includes '|' for sep_char (PR#26)

0.80 - 31 Dec 2018, H.Merijn Brand
    * Raise Spreadsheet::ParseXLSX minimum version to 0.24
    * Improve docs on attributes
    * Add attribute accessors

(wiz)