image-picker添加了对批量添加图片的支持，一次性把所有添加的图片都返回，只触发一次onChange

[melchior-voidwolf]

First of all, thank you for your contribution! :-)

Please makes sure that these checkboxes are checked before submitting your PR, thank you!

• Make sure that you follow antd's code convention.
• Run npm run lint and fix those errors before submitting in order to keep consistent code style.
• Rebase before creating a PR to keep commit history clear.
• Add some descriptions and refer relative issues for you PR.

Extra checklist:

if isBugFix :

• Make sure that you add at least one unit test for the bug which you had fixed.

elif isNewFeature :

• Update API docs for the component.
• Update/Add demo to demonstrate new feature.
• Update TypeScript definition for the component.
• Add unit tests for the feature.

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This change is 

[melchior-voidwolf]

ref：#2895

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@44d1835). Click here to learn what that means.
The diff coverage is 0%.

@@            Coverage Diff            @@
##             master    #3115   +/-   ##
=========================================
  Coverage          ?   60.26%           
=========================================
  Files             ?       92           
  Lines             ?     2265           
  Branches          ?      648           
=========================================
  Hits              ?     1365           
  Misses            ?      891           
  Partials          ?        9

Flag	Coverage Δ
#web	60.26% <0%> (?)

Impacted Files	Coverage Δ
components/image-picker/index.tsx	32.52% <0%> (ø)

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[ziluo]

这里引入Promise后需要check下兼容性问题，项目是否需要额外配置或直接引入polyfill文件 @melchior-voidwolf

[melchior-voidwolf]

这里引入Promise后需要check下兼容性问题，项目是否需要额外配置或直接引入polyfill文件 @melchior-voidwolf

antd-mobile 的官方文档中已经推荐引入 Promise 的 fallback 支持的情况下，处理 fallback 的事情是否还需要内部处理 ?

[ziluo]

还是存在一定的向下兼容风险的，建议在组件文档里强调一下吧 @melchior-voidwolf

[ziluo]

+1