Update history to reflect merge of #594 [ci skip]

Author: jekyllbot

History.markdown

@@ -37,6 +37,7 @@
   * Allow skins to be defined and customized easily (#336)
   * Drop support for scalar 'author' configuration (#384)
   * Place skins in `minima/skins` to clarify purpose (#479)
+  * Add adaptive skin: `solarized` (#594)
 
 ### Bug Fixes