Contributors - update name of contributor from nickname to full name

Author: samaaron

CONTRIBUTORS.md

@@ -187,7 +187,7 @@ into additional languages:
 * Diego Gurnari (4)
 * Thomas G. Kristensen (4)
 * Francisco Llaryora (4)
-* ossa (4)
+* Hayato Osanai (4)
  * [email protected] (4)
 * Martin Zeilinger (3)
 * Yang Wanjun (3)