spelling : it’s -> its (mbeaudru#80)

Author: Nicolapps

README.md

@@ -990,7 +990,7 @@ const xFetcherPromise = new Promise( // Create promise using "new" keyword and s
 
 As seen in the above sample, the Promise object takes an *executor* function which takes two parameters **resolve** and **reject**. Those parameters are functions which when called are going to move the promise *pending* state to respectively a *fulfilled* and *rejected* state.
 
-The promise is in pending state after instance creation and it's *executor* function is executed immediately. Once one of the function *resolve* or *reject* is called in the *executor* function, the promise will call its associated handlers.
+The promise is in pending state after instance creation and its *executor* function is executed immediately. Once one of the function *resolve* or *reject* is called in the *executor* function, the promise will call its associated handlers.
 
 ##### Promise handlers usage