Fix H6 tag in readme (#620)

* There were too many # so it wasn't rendering an h6

* Add a small correction

Co-authored-by: Ruslan Bikkinin <v-rubikk@microsoft.com>

Author: matt-auckland

README.md

@@ -611,7 +611,7 @@ The optional `downloadProgress` callback is invoked several times during the dow
 
     Defines the format of the DownloadProgress object, used to send periodical update notifications on the progress of the update download.
 
-    ####### Properties
+    Properties
 
     - __totalBytes__: The size of the downloading update package, in bytes. (Number)
     - __receivedBytes__: The number of bytes already downloaded. (Number)