Minor improvement to the cws-upload role docs

Change-Id: Ibffabbe9a64ea3ca1e4b77f09378f005c27acda7
diff --git a/roles/cws-upload/README.md b/roles/cws-upload/README.md
index 460e5aa..077f684 100644
--- a/roles/cws-upload/README.md
+++ b/roles/cws-upload/README.md
@@ -11,7 +11,7 @@
 - `autopublish`: whether the updated extension should be published immediately
 after the review completes. (default: `true`)
 - `trustedTesters`: whether the extension should be published only to trusted
-testers.
+testers. (default: `true`)
 
 [1]: https://github.com/fregante/chrome-webstore-upload-cli
 [2]: https://github.com/fregante/chrome-webstore-upload/blob/main/How%20to%20generate%20Google%20API%20keys.md