[FFmpeg-user] How to change recording datetime of WAV files

[Felix E. Klee]

My audio recorder was in a different time zone, plus there was an
inaccuracy of a few minutes:

    $ ffprobe -v quiet -print_format flat -show_format "ZOOM0004.WAV"
    […]
    format.tags.date="2021-09-13"
    format.tags.creation_time="19:21:33"
    […]

This needs to be adjusted by adding 7:56, to read:

    format.tags.date="2021-09-14"
    format.tags.creation_time="03:17:33"

A bunch of files are affected.

How do I best script that?