Update avatar.vue
Update avatar.vue

refs: https://github.com/syuilo/misskey/pull/2182#discussion_r209464350
Tosuke/misskey,Tosuke/misskey,syuilo/Misskey,ha-dai/Misskey,ha-dai/Misskey,syuilo/Misskey,Tosuke/misskey,Tosuke/misskey,Tosuke/misskey