Log Message:
mikutter: update to 3.9.0-alpha2.

Upstream changes:

* quickstep
* crash on a retweet tab in Tweet details tabs when non-Twitter World
  is selected
* pass application name to notify-send
 * thanks Shibafu Midorino
* improve performance of toot cache
* crash on Fav'ed from Mastodon World when Current World is not
  fav'ed account