[macOS] Fix curl error "argument list too long"

[HLFH]

See #396 for details.
The requestbody.txt file is being saved to /Users/MYSUSER/Library/Containers/com.microsoft.Excel/Data and will be removed once the curl command has been executed.

[mohawk2]

Surely the file should be placed in a temporary directory instead? What if the local directory is read-only?

[michaelterryio]

Thanks @HLFH!

[fzumstein]

Surely the file should be placed in a temporary directory instead? What if the local directory is read-only?

@mohawk2 /Users/MYSUSER/Library/Containers/com.microsoft.Excel/Data is indeed one of the few writable directories with modern masOS Excel (since 2016/365): since Excel is sandboxed, external directories (such as /tmp) would require approval first.