TextColor of help content when Form.Item's validate status is warning is unreadable with light theme

[thisrabbit]

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

Reproduction link

Steps to reproduce

/

Just view the template page.

What is expected?

Warning message is as clear and readable as error message, or to say that the yellow color should be darker.

What is actually happening?

Warning message is quite difficult to recognize from white background.

Environment	Info
antd	4.16.13
React	17.0.2
System	Windows 10
Browser	Chrome latest

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WCAG Guidelines for Contrast suggests that the ratio 4.5:1 represents the minimum legibility (AA standard) on the web.

However the yellow color against the white bg's contrast ratio is 1.9:1 (calculated by https://webaim.org/resources/contrastchecker/), which is far from the recommended value, and of course is downgrading real user experiences.

I humbly request to make warning color on text be darker (border color is fine).

Plus:
In case you are interested in this, the contrast ratio between the red color in error status and the white bg is 3.26:1, which also fails the readability test in the link given before.

[UsamaMahboob]

I can work on this!