Expose time taken in result object (#295)

* --added fixed progress bar

* --added props for readme and validation for progress bar input color

* --progressBarColor in quiz object

* --added some changes

* --minor error fixed

* added time spent at QuestionSummary

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Co-authored-by: WK Wong <wingkwong.code@gmail.com>

src/lib/Core.jsx

@@ -80,6 +80,7 @@ function Core({
       userInput,
       totalPoints,
       correctPoints,
+      timeTaken: timer - timeRemaining,
     });
   }, [totalPoints, correctPoints]);