Fail S3 deploy when incompatible filename detected

**Update**: changing this issue to be one to guard against and fail the deploy when incompatible filename detected for S3 deploy. Should provide good feedback to the user of what's going on. Ideally, lookup and guard against this before the deploy processes starts, if possible.

original desc:

Having a `é` in an image file name stops the export process and it takes quitte some time to figure out what is wrong reading the export log. I would be great it these would still work!
Have a great day!