upgrade gh-pages dep

package.json

@@ -69,7 +69,7 @@
     "eslint-plugin-jsx-a11y": "^6.0.3",
     "eslint-plugin-markdown": "^1.0.0-beta.6",
     "eslint-plugin-react": "^7.11.1",
-    "gh-pages": "^1.2.0",
+    "gh-pages": "^2.0.0",
     "husky": "^0.14.3",
     "lint-staged": "^7.2.0",
     "merge-umi-mock-data": "^0.0.3",