Update contributors in package.json

Author: wooorm

package.json

@@ -17,7 +17,9 @@
   "bugs": "https://github.com/syntax-tree/hast-to-hyperscript/issues",
   "author": "Titus Wormer <tituswormer@gmail.com> (http://wooorm.com)",
   "contributors": [
-    "Titus Wormer <tituswormer@gmail.com> (http://wooorm.com)"
+    "Titus Wormer <tituswormer@gmail.com> (http://wooorm.com)",
+    "Jannis Redmann <mail@jannisr.de>",
+    "Koto Hajime <toxictoxer@gmail.com>"
   ],
   "files": [
     "index.js"