Update README.md

base64 request body no longer accepted; use `/upload_url` instead
See #35

README.md

@@ -143,11 +143,7 @@ Users will upload files directly into the `attache` server from their browser, b
 > ```
 > PUT /upload?file=image123.jpg
 > ```
-> file content is the http request body as raw binary (preferred) or encoded as base64 uri like this:
-> ```
-> PUT /upload?file=image123.jpg
-> data:image/jpeg;base64,/9j/4QBiR....
-> ```
+> file content is the http request body
 
 The main app front end will receive a unique `path` for each uploaded file - the only information to store in the main app database.