Merge pull request #21 from rubytaiwan/fix-ydah-gh

Fix GH link of @ydah

Author: ryudoawaru

_data/schedule.yml

@@ -394,7 +394,7 @@
   speaker_id: KVTZHB
   speaker_avatar: ydah_.jpg
   speaker_name: Yudai Takada
-  speaker_github: ydah_
+  speaker_github: ydah
   speaker_x: ydah_
   speaker_bio: CRuby committer. Committer of Lrama, committee. RuboCop RSpec team
   subject: Joy with 3D Graphics Using Ruby