[geary/wip/3-32-appdata] Update README with icon and new screenshot

[Michael Gratton <mjog src gnome org>]

commit 3959fd429d5a6216107ce8f69f11b1619252adb6
Author: Michael Gratton <mike vee net>
Date:   Sun Mar 17 21:15:13 2019 +1100

    Update README with icon and new screenshot

 README.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/README.md b/README.md
index ba5f9e85..f5883ace 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 Geary: Send and receive email
 =============================
 
+![Geary icon](https://wiki.gnome.org/Apps/Geary?action=AttachFile&do=get&target=geary-3-32-256-logo.png)
+
 Geary is an email application built around conversations, for the
 GNOME 3 desktop. It allows you to read, find and send email with a
 straightforward, modern interface.
@@ -13,7 +15,7 @@ translations are managed using GNOME's infrastructure, so we cannot
 accept tickets or pull requests on GitHub. Please see the links below
 for more information.
 
-![Geary displaying a 
conversation](https://wiki.gnome.org/Apps/Geary?action=AttachFile&amp;do=get&amp;target=geary-conversation-0.12.png)
+![Geary displaying a 
conversation](https://wiki.gnome.org/Apps/Geary?action=AttachFile&amp;do=get&amp;target=geary-3-32-main-window.png)
 
 Installation & Licensing
 ------------------------