Remove end "." from summary tag

data/com.github.writeas.writeas-gtk.appdata.xml

@@ -4,7 +4,7 @@
   <project_license>GPL-3.0+</project_license>
   <metadata_license>GPL-3.0+</metadata_license>
   <name>Write.as</name>
-  <summary>Publish a thought in seconds.</summary>
+  <summary>Publish a thought in seconds</summary>
 
   <description>
     <p>Write.as is a simple writing tool and publishing platform. There's no sign up — just open the app, write something, and publish.</p>