Update staging container

Manually uploaded a :1.1 tag for the staging container, now it's alpine based
(1/4th in image size) and no longer has the warning mentioned in #2837.

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

docs/contribute/stage-documentation-changes.md

@@ -61,7 +61,7 @@ for this image.
 1. In the root of your cloned repository, enter this command to start a local
 web server:
 
-        docker run -ti --rm -v "$PWD":/k8sdocs -p 4000:4000 gcr.io/google-samples/k8sdocs:1.0
+        docker run -ti --rm -v "$PWD":/k8sdocs -p 4000:4000 gcr.io/google-samples/k8sdocs:1.1
 
 1. View your staged content at
 [http://localhost:4000](http://localhost:4000){: target="_blank"}.