moves object-assign package to regular deps

Author: syropian

package-lock.json

@@ -51,7 +51,6 @@
     "@vue/test-utils": "^1.0.0-beta.29",
     "babel-jest": "^24.9.0",
     "bili": "^4.8.1",
-    "es6-object-assign": "^1.1.0",
     "gh-pages": "^2.1.1",
     "jest": "^24.9.0",
     "node-sass": "^4.5.3",
@@ -61,5 +60,7 @@
     "vue-highlightjs": "^1.3.3",
     "vue-template-compiler": "^2.6.8"
   },
-  "dependencies": {}
+  "dependencies": {
+    "es6-object-assign": "^1.1.0"
+  }
 }