v2.2.2 - Fix 'progress' callback timetravel

• This bug was tracked in #30. On certain file sizes the progress event would travel back in time. The bug did not affect usability, but it was rather jarring and unexpected for users. Imagine seeing a progress bar inching up as your file is uploaded and then bam all of a sudden when it gets to ~50% it jumps back in time to 33%, and then after that it jumps up to 51%. That's no good.
• Thankfully @michaellimair squashed this 🐛 in #43 (and with great test coverage to boot! 🥾 ). Thanks Michael!