docs: update node version in readme (#381)

[ci skip]
electron-rebuild 2.0.0 depends on node >=10.0.0

README.md

@@ -43,7 +43,7 @@ npm run rebuild
 
 ### What are the requirements?
 
-Node v6.0.0 or higher is required. Building the native modules from source uses
+Node v10.0.0 or higher is required. Building the native modules from source uses
 [`node-gyp`](https://github.com/nodejs/node-gyp#installation), refer to the link for its
 installation/runtime requirements.