Consider removal of deprecated elements as compatible

I'm using openapi-diff quite successfully to avoid accidental changes in the API (and therefore introducing a breaking change). We use it as a part of our pipeline.

The current struggle is: that sometimes one wants to introduce a breaking change (like the removal of obsolete API).
My initial idea would float around a two-step process:

• marking an element ad deprecated (keeping compatibility)
• removing the deprecated element

To do that, when processing the list of ChangedOpenApi#getChangedElements I'd need to know if the particular element is deprecatable and decide if the change is incompatible or not.

That looks to me like another SPI but I'm not sure if it's the direction. I know it's currently not possible and I'm not even sure if the direction of my thought even makes sense.

首先检查 ChangedOpenApi#getChangedElements，以及 openapi-diff 当前如何将删除分类为不兼容。在决定采用哪种方案之前，先审查现有的扩展点和 issue 中提出的 SPI 思路。Done 应提供一种明确的方式，将删除已弃用元素视为兼容，同时保留现有的 breaking-change 检查。