createrelease: updated backup instructions [skip ci] - #8875

The current running Python version 3.10.12 is older than 3.14. It works fine with aqtinstall in most cases, but may have bugs with file type detection. If you are experiencing errors related to "zipfile.BadZipFile", please upgrade Python. For details, please see upstream report: https://github.com/miurahr/aqtinstall/issues/1042