_onArrowUpKeyDown() {
    if (this.filteredOptions.length > 0) {
      let index = this.filteredOptions.length - 1;
      if (this.state.focusedOptionIndex) {
        index = this.state.focusedOptionIndex - 1;
      }

      this.setState({
        focusedOptionIndex: index,
      });
    }
  }
Highlight previous option when arrowUp key is pressed.
Highlight last option if currently first option is focused.