message: refactor(stepedge): use smooth step edge with border radius=0
diff: import React, { memo } from 'react';
  -import EdgeText from './EdgeText';
  -import { getMarkerEnd } from './utils';
  -import { EdgeProps } from '../../types';
  +import { EdgeSmoothStepProps } from '../../types';
  +import SmoothStepEdge from './SmoothStepEdge';
  -interface GetStepPathParams {
  - centerY: number;
  - sourceX: number;
  - sourceY: number;
  - targetX: number;
  - targetY: number;
  -}
  -
  -export function getStepPath({ centerY, sourceX, sourceY, targetX, targetY }: GetStepPathParams): string {
  - return `M ${sourceX},${sourceY}L ${sourceX},${centerY}L ${targetX},${centerY}L ${targetX},${targetY}`;
  -}
  -
  -export default memo(
  - ({
  - sourceX,
  - sourceY,
  - targetX,
  - targetY,
  - label,
  - labelStyle,
  - labelShowBg,
  - labelBgStyle,
  - style,
  - arrowHeadType,
  - markerEndId,
  - }: EdgeProps) => {
  - const yOffset = Math.abs(targetY - sourceY) / 2;
  - const centerY = targetY < sourceY ? targetY + yOffset : targetY - yOffset;
  -
  - const xOffset = Math.abs(targetX - sourceX) / 2;
  - const centerX = targetX < sourceX ? targetX + xOffset : targetX - xOffset;
  -
  - const path = getStepPath({ centerY, sourceX, sourceY, targetX, targetY });
  -
  - const markerEnd = getMarkerEnd(arrowHeadType, markerEndId);
  -
  - const text = label ? (
  - <EdgeText
  - x={centerX}
  - y={centerY}
  - label={label}
  - labelStyle={labelStyle}
  - labelShowBg={labelShowBg}
  - labelBgStyle={labelBgStyle}
  - />
  - ) : null;
  -
  - return (
  - <>
  - <path style={style} className="react-flow__edge-path" d={path} markerEnd={markerEnd} />
  - {text}
  - </>
  - );
  - }
  -);
  +export default memo((props: EdgeSmoothStepProps) => {
  + return <SmoothStepEdge {...props} borderRadius={0} />;
  +});
  