g2 legend不支持自定义html样式 #2954

• I have searched the issues of this repository and believe that this is not a duplicate.

What problem does this feature solve?

3.0支持containerTpl参数。4.0直接移除了，并且没有找到响应升级的语法

What does the proposed API look like?

支持containerTpl，或者是否有其他方式实现

<!-- generated by antv-issue-helper. DO NOT REMOVE -->