Fix yarn workspaces explanation

packages/tslint-config/README.md

@@ -11,6 +11,7 @@ yarn add --dev @0xproject/tslint-config
 
 ## Usage
 
+Add the following to your `tslint.json` file
 ```json
 {
   "extends": [
@@ -27,7 +28,7 @@ Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting
 
 ### Install Dependencies
 
-If you don't have yarn workspaces enabled - enable them:
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
 ```bash
 yarn config set workspaces-experimental true
 ```