Updated README.md

Added yarn support command to install the package.

Author: Ishaan28malik

README.md

@@ -6,6 +6,10 @@ added. An infinite-scroll that actually works and super-simple to integrate!
 # install
 ```bash
   npm install --save react-infinite-scroll-component
+  
+  or
+  
+  yarn add react-infinite-scroll-component 
 
   // in code ES6
   import InfiniteScroll from 'react-infinite-scroll-component';
@@ -82,4 +86,4 @@ name | type | description
 **pullDownToRefreshThreshold** | number | minimum distance the user needs to pull down to trigger the refresh, `default=100px`
 **refreshFunction** | function | this function will be called, it should return the fresh data that you want to show the user
 **initialScrollY** | number | set a scroll y position for the component to render with.
-**key** | string | the key for the current data set being shown, used when the same component can show different data sets at different times, `default=undefined`
+**key** | string | the key for the current data set being shown, used when the same component can show different data sets at different times, `default=undefined`