Updated screenshot.

git-svn-id: https://plugins.svn.wordpress.org/easy-testimonials/trunk@832418 b8457f37-d9ea-0310-8a92-e5e31aec5664
Accidentally committed wrong image.

git-svn-id: https://plugins.svn.wordpress.org/easy-testimonials/trunk@832419 b8457f37-d9ea-0310-8a92-e5e31aec5664