fix(deps): move umi-mock-middleware -> dev

Author: sendya

package.json

@@ -17,7 +17,6 @@
     "mockjs": "^1.1.0",
     "store": "^2.0.12",
     "nprogress": "^0.2.0",
-    "umi-mock-middleware": "^1.0.0",
     "vue": "^2.6.11",
     "vue-i18n": "^8.20.0",
     "vue-router": "^3.2.0",
@@ -42,6 +41,7 @@
     "eslint-plugin-standard": "^4.0.0",
     "eslint-plugin-vue": "^6.2.2",
     "git-revision-webpack-plugin": "^3.0.6",
+    "umi-mock-middleware": "^1.0.0",
     "less": "^3.0.4",
     "less-loader": "^5.0.0",
     "lint-staged": "^9.5.0",