Release v1.6.0 (#324)

* Update version and changelog for v1.6.0
* Update docs
diff --git a/docs/dyn/gamesConfiguration_v1configuration.imageConfigurations.html b/docs/dyn/gamesConfiguration_v1configuration.imageConfigurations.html
index 05d8a8a..5b99373 100644
--- a/docs/dyn/gamesConfiguration_v1configuration.imageConfigurations.html
+++ b/docs/dyn/gamesConfiguration_v1configuration.imageConfigurations.html
@@ -75,11 +75,11 @@
 <h1><a href="gamesConfiguration_v1configuration.html">Google Play Game Services Publishing API</a> . <a href="gamesConfiguration_v1configuration.imageConfigurations.html">imageConfigurations</a></h1>
 <h2>Instance Methods</h2>
 <p class="toc_element">
-  <code><a href="#upload">upload(resourceId, imageType, media_body=None)</a></code></p>
+  <code><a href="#upload">upload(resourceId, imageType, media_body=None, media_mime_type=None)</a></code></p>
 <p class="firstline">Uploads an image for a resource with the given ID and image type.</p>
 <h3>Method Details</h3>
 <div class="method">
-    <code class="details" id="upload">upload(resourceId, imageType, media_body=None)</code>
+    <code class="details" id="upload">upload(resourceId, imageType, media_body=None, media_mime_type=None)</code>
   <pre>Uploads an image for a resource with the given ID and image type.
 
 Args:
@@ -89,6 +89,7 @@
       ACHIEVEMENT_ICON - The icon image for an achievement resource.
       LEADERBOARD_ICON - The icon image for a leaderboard resource.
   media_body: string, The filename of the media request body, or an instance of a MediaUpload object.
+  media_mime_type: string, The MIME type of the media request body, or an instance of a MediaUpload object.
 
 Returns:
   An object of the form: