I am a bit confused on this quote, can you clarify?
"upload and updated version of the workbook back to the same file name without having to overwrite its name"
If you want to update a workbook that already exists on Tableau Online, you can simply make the changes in Tableau Desktop, republish the workbook with the same name, and it will overwrite the existing copy with the new copy which contains the updated story or dashboard within that workbook.
You can also use revision history, so end users can preview or download old versions of the workbook if needed: Work with Content Revisions
Hope this info is helpful!