Update progress callback parameter names in README

Author: Zhoucheng133

plugins/upload/README.md

@@ -66,15 +66,15 @@ import { upload, HttpMethod } from '@tauri-apps/plugin-upload'
 upload(
   'https://example.com/file-upload',
   './path/to/my/file.txt',
-  (progress, total) => console.log(`Uploaded ${progress} of ${total} bytes`), // a callback that will be called with the upload progress
+  (progressTotal, total) => console.log(`Uploaded ${progressTotal} of ${total} bytes`), // a callback that will be called with the upload progress
   { 'Content-Type': 'text/plain' } // optional headers to send with the request
 )
 
 // Upload with specific HTTP method
 upload(
   'https://example.com/file-upload',
   './path/to/my/file.txt',
-  (progress, total) => console.log(`Uploaded ${progress} of ${total} bytes`),
+  (progressTotal, total) => console.log(`Uploaded ${progressTotal} of ${total} bytes`),
   { 'Content-Type': 'text/plain' },
   HttpMethod.Put // Use HttpMethod enum - supports POST, PUT, PATCH
 )
@@ -86,7 +86,7 @@ import { download } from '@tauri-apps/plugin-upload'
 download(
   'https://example.com/file-download-link',
   './path/to/save/my/file.txt',
-  (progress, total) => console.log(`Downloaded ${progress} of ${total} bytes`), // a callback that will be called with the download progress
+  (progressTotal, total) => console.log(`Downloaded ${progressTotal} of ${total} bytes`), // a callback that will be called with the download progress
   { 'Content-Type': 'text/plain' } // optional headers to send with the request
 )
 ```