Change default Android theme color meta tag (#389)

conf/app.ini

@@ -57,7 +57,7 @@ FEED_MAX_COMMIT_NUM = 5
 ; Value of `theme-color` meta tag, used by Android >= 5.0
 ; An invalid color like "none" or "disable" will have the default style
 ; More info: https://developers.google.com/web/updates/2014/11/Support-for-theme-color-in-Chrome-39-for-Android
-THEME_COLOR_META_TAG = `#ff5343`
+THEME_COLOR_META_TAG = `#6cc644`
 ; Max size of files to be displayed (defaults is 8MiB)
 MAX_DISPLAY_FILE_SIZE = 8388608