fix: use space in accept-encoding values (node-fetch#1572)

* fix for issue node-fetch#1571

* Update README.md

Co-authored-by: Jimmy Wärting <[email protected]>

Author: tmclo

README.md

@@ -537,7 +537,7 @@ If no values are set, the following request headers will be sent automatically:
 
 | Header              | Value                                                  |
 | ------------------- | ------------------------------------------------------ |
-| `Accept-Encoding`   | `gzip,deflate,br` _(when `options.compress === true`)_ |
+| `Accept-Encoding`   | `gzip, deflate, br` (when `options.compress === true`) |
 | `Accept`            | `*/*`                                                  |
 | `Connection`        | `close` _(when no `options.agent` is present)_         |
 | `Content-Length`    | _(automatically calculated, if possible)_              |

src/request.js

@@ -280,7 +280,7 @@ export const getNodeRequestOptions = request => {
 
 	// HTTP-network-or-cache fetch step 2.15
 	if (request.compress && !headers.has('Accept-Encoding')) {
-		headers.set('Accept-Encoding', 'gzip,deflate,br');
+		headers.set('Accept-Encoding', 'gzip, deflate, br');
 	}
 
 	let {agent} = request;