Bump version number to 10.6.0 so everybody gets release notes

There are important notices in the release notes that everyone needs
to see so I'm bumping the version number to 10.6.0 without any
functional changes to force the display of the release notes on
upgrade.

manifest.json

@@ -5,7 +5,7 @@
 
   "description": "__MSG_extensionDescription__",
 
-  "version": "10.5.8",
+  "version": "10.6.0",
 
   "homepage_url": "https://github.com/Extended-Thunder/send-later/",