upgrade lerna

Author: AllenFang

package.json

@@ -1,6 +1,7 @@
 {
   "name": "react-bootstrap-table2",
   "version": "0.0.1",
+  "private": true,
   "description": "Rebuilt for react-bootstrap-table",
   "main": "index.js",
   "scripts": {
@@ -20,11 +21,13 @@
     "url": "git+https://github.com/react-bootstrap-table/react-bootstrap-table2.git"
   },
   "author": "AllenFang",
-  "contributors": [{
-    "name": "Chun-MingChen",
-    "email": "nick830314@gmail.com",
-    "url": "https://github.com/Chun-MingChen"
-  }],
+  "contributors": [
+    {
+      "name": "Chun-MingChen",
+      "email": "nick830314@gmail.com",
+      "url": "https://github.com/Chun-MingChen"
+    }
+  ],
   "license": "MIT",
   "bugs": {
     "url": "https://github.com/react-bootstrap-table/react-bootstrap-table2/issues"
@@ -60,7 +63,7 @@
     "jest": "20.0.4",
     "jsdom": "11.2.0",
     "jsdom-global": "3.0.2",
-    "lerna": "2.0.0",
+    "lerna": "2.8.0",
     "node-sass": "4.5.3",
     "react-test-renderer": "16.0.0",
     "sass-loader": "6.0.6",