react multi step change the button text on specific step

Question

I am using the following code where I am trying to change few things

https://github.com/srdjan/react-multistep

In the last step I am trying to change the button text as Submit instead of continue but couldn't also the last button was always in disabled state. Here is the code I am working out

https://codesandbox.io/s/59gqjg

This is the code I had for the MultiStep one

 <div>
   <MultiStep
       // activeStep={0}
       prevButton={{
       disabled: true,
       style: {
           'float': 'right',
           'margin': '5px',
           'border': '1px solid #e20074',
           'backgroundColor': 'transparent',
           'color': '#E20074',
           'width': '120px',
           'height': '40px',
       },
        title: 'Back'
      }}

  nextButton={{
    //disabled: false,
    style: {
      'backgroundColor': '#E20074',
      'color': '#fff',
      'width': '150px',
       'height': '40px',
       'borderRadius': '3px',
       'border': '1px solid #e20074',
       'float': 'right',
       'margin': '5px'
      },
       title: 'Continue',
        onClick: nextClick // Call your custom function here
    }}
>
     <FormFeilds title="Feilds"></FormFeilds>
     <FeildsandConditions title='FeildsandConditions'>
     </FeildsandConditions>
     <ReviewAndSubmit title="ReviewAndSubmit"></ReviewAndSubmit>
   </MultiStep>
  </div>
 </div>