Updated website docs added total upload progress event (#2637)

* chore: updated docs added total upload progress

* Update website/src/docs/uppy.md

Co-authored-by: Renée Kooi <renee@kooi.me>

* Update website/src/docs/uppy.md

Co-authored-by: lol <lol@lols-MacBook-Pro.local>
Co-authored-by: Artur Paikin <artur@arturpaikin.com>
Co-authored-by: Renée Kooi <renee@kooi.me>

website/src/docs/uppy.md

@@ -767,9 +767,25 @@ uppy.on('upload', (data) => {
 })
 ```
 
+### `progress`
+
+Fired each time the total upload progress is updated:
+
+**Parameters**
+- `progress` - An integer (0-100) representing the total upload progress.
+
+**Example**
+
+```javascript
+uppy.on('progress', (progress) => {
+  // progress: integer (total progress percentage)
+  console.log(progress)
+})
+```
+
 ### `upload-progress`
 
-Fired each time file upload progress is available:
+Fired each time an individual file upload progress is available:
 
 **Parameters**
 - `file` - The [File Object][File Objects] for the file whose upload has progressed.