Version bump; update changelog for 0.7.3

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

CHANGELOG.md

 # Changelog
 All notable changes to this project will be documented in this file.
 
+## 0.7.3 – 2017-09-12
+### Fixed
+- Notification favicon for incoming messages
+- Background sync if only one account is configured
+- Error propagation in case folders cannot be loaded
+
 ## 0.7.2 – 2017-09-06
 ### Added
 - Earlier loading feedback

appinfo/info.xml

@@ -5,7 +5,7 @@
 	<name>Mail</name>
 	<summary>IMAP web client</summary>
 	<description>Easy to use email client which connects to your mail server via IMAP and SMTP.</description>
-	<version>0.7.2</version>
+	<version>0.7.3</version>
 	<licence>agpl</licence>
 	<author>Christoph Wurst</author>
 	<author>Jan-Christoph Borchardt</author>