title: Material UI DatePicker set to Required
body: <p>i am using the Material UI DatePicker in my react app and need to set the date to be required?</p>
  
  <p>Do I need to create a custom validator checking value on submit or is there a prop I can use to set field to required?</p>
  
  <pre><code>&lt;DatePicker
              spacing={2}
              PopoverProps={{ container: this.props.container }}
              onChange={this.updateEndDate}
              value={this.state.endDate}
              initialFocusedDate={this.state.startDate}
              minDate={this.state.startDate}
              disablePast="true"
              disableToolbar="true"
              variant="inline"
              label="End Date"
  
             // I have tried adding required, required="true", required={true}
  
  
            /&gt;
  </code></pre>