allOf : `type` of property contained in multiple subschemas is not correctly determined.

Given the following schema V1:

Foo:
  allOf:
    - properties:
        propA:
          type: string
    - properties:
        propA:
          example: "YEEHAA"

is changed to the following schema V2:

Foo:  
  properties:
    propA:
      type: string

openapi-diff incorrectly detects the following incompatible change:
Changed property type (object -> string)

It seems to me that the type of a property that is contained in multiple subschemas of an allOf is not correctly determined. Openapi-diff recognized the type of propA in schema V1 as an object, but this is not correct.

首先重现所提供的 V1 和 V2 schema 之间的比较，重点关注 Foo、allOf 以及重复的 propA 定义。检查 diff 如何在所有 allOf 子 schema 中确定 propA 的类型。完成的标准是：对于此案例，比较结果不再报告从 object 到 string 的不兼容类型变更。