修改文档使用expo sdk32以上版本时出现的问题

[guowenzhuang]

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.

[codecov]

Codecov Report

Merging #535 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #535   +/-   ##
=======================================
  Coverage   59.07%   59.07%           
=======================================
  Files         197      197           
  Lines        4990     4990           
  Branches     1094     1094           
=======================================
  Hits         2948     2948           
  Misses       2025     2025           
  Partials       17       17

Flag	Coverage Δ
#rn	59.07% <ø> (ø)	⬆️

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