add devdependences

Author: XuanmiaoG

package.json

@@ -22,5 +22,8 @@
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },
-  "version": "0.1.6"
+  "devDependencies": {
+    "hexo": "^6.0.0"
+  },
+  "version": "0.1.8"
 }